Poor achievement of guidelines-recommended targets in type 2 diabetes: findings from a contemporary prospective cohort study.

AIMS: To prospectively evaluate diabetes management in the primary care setting and explore factors related to guideline-recommended triple target achievement [blood pressure (BP) ≤ 130/80 mmHg, A1C ≤ 7% and low-density lipoprotein (LDL)-cholesterol < 2.5 mmol/l]. METHODS: Baseline, 6 and 12 month data on clinical and laboratory parameters were measured in 3002 patients with type 2 diabetes enrolled as part of a prospective quality enhancement research initiative in Canada. A generalised estimating equation model was fitted to assess variables associated with triple target achievement. RESULTS: At baseline, 54%, 53% and 64% of patients, respectively, had BP, A1C and LDL-cholesterol at target; all three goals were met by 19% of patients. The percentage of individuals achieving these targets significantly increased during the study [60%, 57%, 76% and 26%, respectively, at the final visit, p < 0.0001 except for A1C, p = 0.27]. A much smaller proportion of patients had adequate control during the entire study period [30%, 39%, 53% and 7%, respectively]. In multivariable analysis, women, patients younger than 65 years and patients of Afro-Canadian origin were less likely to achieve the triple target. DISCUSSION: As part of a quality enhancement research initiative, we observed important improvements in the attainment of guidelines-recommended targets in patients with type 2 diabetes followed for a 12-month period in the primary care setting; however, many individuals still failed to achieve and especially maintain optimal goals for therapy, particularly the triple target. Results of the multivariable analysis reinforce the need to address barriers to improve diabetes care, particularly in more susceptible groups.

CCS/CAR/CANM/CNCS/CanSCMR joint position statement on advanced noninvasive cardiac imaging using positron emission tomography, magnetic resonance imaging and multidetector computed tomographic angiography in the diagnosis and evaluation of ischemic heart disease--executive summary.

BACKGROUND: Over the past few decades, advanced imaging modalities with excellent diagnostic capabilities have emerged. The aim of the present position statement was to systematically review existing literature to define Canadian recommendations for their clinical use. METHODS: A systematic literature review to 2005 was conducted for positron emission tomography (PET), multidetector computed tomographic angiography and magnetic resonance imaging (MRI) in ischemic heart disease. Papers that met the criteria were reviewed for accuracy, prognosis data and study quality. Recommendations were presented to primary and secondary panels of experts, and consensus was achieved. RESULTS: Indications for PET include detection of coronary artery disease (CAD) with perfusion imaging, and defining viability using fluorodeoxyglucose to determine left ventricular function recovery and/or prognosis after revascularization (class I). Detection of CAD in patients, vessel segments and grafts using computed tomographic angiography was considered class IIa at the time of the literature review. Dobutamine MRI is class I for CAD detection and, along with late gadolinium enhancement MRI, class I for viability detection to predict left ventricular function recovery. Imaging must be performed at institutions and interpreted by physicians with adequate experience and training. CONCLUSIONS: Cardiac imaging using advanced modalities (PET, multidetector computed tomographic angiography and MRI) is useful for CAD detection, viability definition and, in some cases, prognosis. These modalities complement the more widespread single photon emission computed tomography and echocardiography. Given the rapid evolution of technology, initial guidelines for clinical use will require regular updates. Evaluation of their integration in clinical practice should be ongoing; optimal use will require proper training. A joint effort among specialties is recommended to achieve these goals.

Treating the right patient at the right time: Access to echocardiography in Canada.

The Canadian Cardiovascular Society is the national professional society for cardiovascular specialists and researchers in Canada. In the spring of 2004, the Canadian Cardiovascular Society Council formed the Access to Care Working Group ('Working Group') to use the best science and information available to establish reasonable triage categories and safe wait times for access to common cardiovascular procedures. The Working Group decided to publish a series of commentaries to initiate a structured national discussion on this important issue, and the present commentary proposes recommended wait times for access to echocardiography. 'Emergent' echocardiograms should be performed within 24 h, 'urgent' within seven days and 'scheduled' (elective) within 30 days. A framework for a solution-oriented approach to improve access is presented.

The 2000 Canadian recommendations for the management of hypertension: Part one--therapy.

OBJECTIVE: To provide updated, evidence-based recommendations for the therapy of hypertension in adults. OPTIONS: For patients with hypertension, there are a number of lifestyle manoeuvres and antihypertensive agents that may control blood pressure. Randomized trials evaluating first- line therapy with thiazides, beta-adrenergic antagonists, angiotensin-converting enzyme inhibitors, calcium channel blockers, alpha-blockers, centrally acting agents or angiotensin II receptor antagonists were reviewed. OUTCOMES: The health outcomes considered were changes in blood pressure, cardiovascular morbidity, and cardiovascular and/or all-cause mortality rates. Economic outcomes were not considered due to insufficient evidence. EVIDENCE: Medline searches were conducted from the period of the last revision of the Canadian Recommendations for the Management of Hypertension (May 1998 to October 2000). Reference lists were scanned, experts were polled, and the personal files of the subgroup members and authors were used to identify other studies. All relevant articles were reviewed and appraised, using prespecified levels of evidence, by content experts and methodological experts. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and mortality. BENEFITS, HARMS, AND COSTS: Various lifestyle manoeuvres and antihypertensive agents reduce the blood pressure of patients with sustained hypertension. In certain settings, and for specific classes of drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and/or mortality. RECOMMENDATIONS: The present document contains detailed recommendations pertaining to all aspects of the therapy of patients with hypertension, including lifestyle modifications proven to lower blood pressure, treatment thresholds, target blood pressures, choice of agents in various settings and strategies to enhance adherence. Lower thresholds for blood pressure treatment are advocated for people with other cardiovascular risk factors or established hypertensive target organ damage. Implicit in the recommendations for therapy is the principle that treatment should be individualized for each patient and the choice of agent should be dictated by coexistent conditions. For the treatment of uncomplicated essential hypertension, thiazides, beta-adrenergic antagonists, angiotensin-converting enzyme inhibitors or calcium channel blockers may be appropriate, depending on individual circumstances. VALIDATION: All recommendations were graded according to strength of the evidence and voted on by the Canadian Hypertension Recommendations Working Group. Only those recommendations achieving high levels of consensus are reported here. These guidelines will be updated annually.

The 2000 Canadian recommendations for the management of hypertension: part two--diagnosis and assessment of people with high blood pressure.

OBJECTIVE: To provide updated, evidence-based recommendations for the diagnosis and assessment of high blood pressure in adults. OPTIONS: For people with high blood pressure, the assignment of a diagnosis of hypertension depends on the appropriate measurement of blood pressure, the level of the blood pressure elevation, the duration of follow-up and the presence of concomitant vascular risk factors, target organ damage and established atherosclerotic diseases. For people diagnosed with hypertension, defining the overall risk of adverse cardiovascular outcomes requires laboratory testing, a search for target organ damage and an assessment of the modifiable causes of hypertension. Out-of-clinic blood pressure assessment and echocardiography are options for selected patients. OUTCOMES: People at increased risk of adverse cardiovascular outcomes and were identified and quantified. EVIDENCE: Medline searches were conducted from the period of the last revision of the Canadian recommendations for the management of hypertension (May 1998 to October 2000). Reference lists were scanned, experts were polled, and the personal files of the subgroup members and authors were used to identify other studies. All relevant articles were reviewed and appraised, using prespecified levels of evidence, by content experts and methodological experts. VALUES: A high value was placed on the identification of people at increased risk of cardiovascular morbidity and mortality. BENEFITS, HARMS AND COSTS: The identification of people at higher risk of cardiovascular disease will permit counselling for lifestyle manoeuvres and the introduction of antihypertensive drugs to reduce blood pressure for patients with sustained hypertension. In certain settings, and for specific classes of drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and/or mortality. RECOMMENDATIONS: The present document contains detailed recommendations pertaining to aspects of the diagnosis and assessment of patients with hypertension, including the accurate measurement of blood pressure, criteria for the diagnosis of hypertension and recommendations for follow-up, routine and optional laboratory testing, assessment for renovascular hypertension, home and ambulatory blood pressure monitoring, and the role of echocardiography in hypertension. VALIDATION: All recommendations were graded according to strength of the evidence and voted on by the Canadian Hypertension Recommendations Working Group. Only the recommendations achieving high levels of consensus are reported here. These guidelines will be updated annually. ENDORSEMENT: These recommendations are endorsed by the Canadian Hypertension Society, The Canadian Coalition for High Blood Pressure Prevention and Control, The College of Family Physicians of Canada, The Heart and Stroke Foundation of Canada, The Adult Disease Division and Bureau of Cardio-Respiratory Diseases and Diabetes at the Centre for Chronic Disease Prevention and Control of Health Canada.

Hemodynamic and physical performance during maximal exercise in patients with an aortic bioprosthetic valve: comparison of stentless versus stented bioprostheses.

OBJECTIVES: The objective of this study was to compare stentless bioprostheses with stented bioprostheses with regard to their hemodynamic behavior during exercise. BACKGROUND: Stentless aortic bioprostheses have better hemodynamic performances at rest than stented bioprostheses, but very few comparisons were performed during exercise. METHODS: Thirty-eight patients with normally functioning stentless (n = 19) or stented (n = 19) bioprostheses were submitted to a maximal ramp upright bicycle exercise test. Valve effective orifice area and mean transvalvular pressure gradient at rest and during peak exercise were successfully measured using Doppler echocardiography in 30 of the 38 patients. RESULTS: At peak exercise, the mean gradient increased significantly less in stentless than in stented bioprostheses (+5 +/- 3 vs. +12 +/- 8 mm Hg; p = 0.002) despite similar increases in mean flow rates (+137 +/- 58 vs. +125 +/- 65 ml/s; p = 0.58); valve area also increased but with no significant difference between groups. Despite this hemodynamic difference, exercise capacity was not significantly different, but left ventricular (LV) mass and function were closer to normal in stentless bioprostheses. Overall, there was a strong inverse relation between the mean gradient during peak exercise and the indexed valve area at rest (r = 0.90). CONCLUSIONS: Hemodynamics during exercise are better in stentless than stented bioprostheses due to the larger resting indexed valve area of stentless bioprostheses. This is associated with beneficial effects with regard to LV mass and function. The relation found between the resting indexed valve area and the gradient during exercise can be used to project the hemodynamic behavior of these bioprostheses at the time of operation. It should thus be useful to select the optimal prosthesis given the patient's body surface area and level of physical activity.

Usefulness of the indexed effective orifice area at rest in predicting an increase in gradient during maximum exercise in patients with a bioprosthesis in the aortic valve position.

This study examines the hemodynamic behavior of aortic bioprosthetic valves during maximum exercise. Nineteen patients with a normally functioning stented bioprosthetic valve and preserved left ventricular function were submitted to maximum ramp bicycle exercise. In 14 of the 19 patients, valve effective orifice area and mean gradient were measured at rest and during exercise using Doppler echocardiography. At peak exercise (mean maximal workload 118 +/- 53 W), the cardiac index increased by 122 +/- 34% (+3.18 +/- 0.71 L/min/ m2, p <0.001), whereas mean gradient increased by 94 +/- 49% (+12 +/- 8 mm Hg, p <0.001), and effective orifice area by 9 +/- 13% (+0.15 +/- 0.22 cm2, p = 0.02). A strong correlation was found between the increase in mean gradient during maximum exercise and the valve area at rest indexed for body surface area (r = 0.84, p <0.0001). Due to the increase in valve area, the increase in gradient was less (-9 +/- 7 mm Hg, -41 +/- 33%, p = 0.0006) than theoretically predicted assuming a fixed valve area. These results suggest that the effective orifice area of the bioprostheses has the capacity to increase during exercise; therefore, limiting the increase in gradient. The relation found between the indexed effective orifice area at rest and the increase in gradient during exercise should be useful in predicting the hemodynamic behavior of a stented bioprosthesis during exercise.

1999 Canadian recommendations for the management of hypertension. Task Force for the Development of the 1999 Canadian Recommendations for the Management of Hypertension.

OBJECTIVE: To provide updated, evidence-based recommendations for health care professionals on the management of hypertension in adults. OPTIONS: For patients with hypertension, there are both lifestyle options and pharmacological therapy options that may control blood pressure. For those patients who are using pharmacological therapy, a range of antihypertensive drugs is available. The choice of a specific antihypertensive drug is dependent upon the severity of the hypertension and the presence of other cardiovascular risk factors and concurrent diseases. OUTCOMES: The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered. EVIDENCE: MEDLINE searches were conducted from the period of the last revision of the Canadian Recommendations for the Management of Hypertension (January 1993 to May 1998). Reference lists were scanned, experts were polled and the personal files of the authors were used to identify other studies. All relevant articles were reviewed, classified according to study design and graded according to levels of evidence. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension. BENEFITS: Harms and costs: The diagnosis and treatment of hypertension with pharmacological therapy will reduce the blood pressure of patients with sustained hypertension. In certain settings, and for specific drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and mortality. RECOMMENDATIONS: This document contains detailed recommendations pertaining to all aspects of the diagnosis and pharmacological therapy of hypertensive patients. With respect to diagnosis, the recommendations endorse the greater use of non-office-based measures of blood pressure control (i.e., using home blood pressure and automatic ambulatory blood pressure monitoring equipment) and greater emphasis on the identification of other cardiovascular risk factors, both in the assessment of prognosis in hypertension and in the choice of therapy. On the treatment side, lower targets for blood pressure control are advocated for some subgroups of hypertensive patients, in particular, those with diabetes and renal disease. Implicit in the recommendations for therapy is the principle that for the vast majority of hypertensive patients treated pharmacologically, practitioners should not follow a stepped-care approach. Instead, therapy should be individualized, based on consideration of concurrent diseases, both cardiovascular and noncardiovascular. VALIDATION: All recommendations were graded according to the strength of the evidence and the consensus of all relevant stakeholders. SPONSORS: The Canadian Hypertension Society and the Canadian Coalition for High Blood Pressure Prevention and Control.

Effect of angiotensin-converting enzyme inhibitor therapy in mitral regurgitation with normal left ventricular function.

Mitral regurgitation (MR) is a common, frequently asymptomatic valvulopathy that can ultimately lead to left ventricular failure. With the objective of forestalling MR progression, a prospective, placebo controlled, double-blind study was conducted. It measured the effectiveness of lisinopril, an angiotensin-converting enzyme inhibitor, in reducing the echocardiographic signs of MR severity over a one-year period. Severe coronary disease was excluded by stress echocardiography. Treatment effectiveness was estimated to be proportional to the reduction in MR fraction and cardiac chamber dimensions, compared with baseline, according to intention-to-treat analysis. A final patient population of 23 asymptomatic adults aged 53.3 +/- 2.4 years (mean +/- SEM), with moderate, organic MR and normal left ventricular function was selected from the echocardiographic database. All baseline patient characteristics were comparable in the two treatment groups, including the MR fraction (55 +/- 3%). Twelve patients received lisinopril (18 +/- 1 mg) and 11 received placebo. After one year of treatment, a statistically significant difference in the MR fraction was observed between the two groups. For the lisinopril group the MR fraction dropped by 6.4 +/- 3.5% and for the placebo group it increased by 3.7 +/- 3.2% versus baseline (P < 0.05). No differences in left atrial or ventricular dimensions were observed. The study drug was stopped in four patients after one patient presented with rapid atrial fibrillation and angina while three patients were intolerant to lisinopril. Only one patient receiving placebo was taken off therapy. In conclusion, treatment with lisinopril indicates some reduction in the severity of chronic moderate MR in asymptomatic patients with normal left ventricular function. This approach appears to be safe, but side effects are not uncommon, warranting regular follow-up.

Estimation of pulmonary artery pressure by spectral analysis of the second heart sound.

The objective of the present work was to test and validate a noninvasive method based on spectral analysis of the second heart sound (S2) to estimate the pulmonary artery (PA) systolic pressure in 89 patients with a bioprosthetic heart valve. The technique was compared with continuous-wave Doppler estimation of PA systolic pressure in these patients. The heart sounds recorded at the pulmonary area on the chest wall were digitized by computer. The spectra of S2 and those of the aortic (A2) and the pulmonary (P2) components of S2 were computed with a fast-Fourier transform. Seven features were extracted from these spectra. The statistical analysis performed with the Pearson linear correlation coefficient showed that the best estimation of PA systolic pressure obtained by spectral phonocardiography (r = 0.84, SEE +/- 5.6 mm Hg, p <0.0001) was provided by the following equation: PA systolic pressure = 47 + 0.68 Fp - 4.4 Qp - 17 Fp/Fa - 0.15 Fs, where Fs and Fp are dominant frequencies associated with the maximal amplitude of the power spectra of S2 and P2, respectively, Qp is the quality of resonance of P2, and Fp/Fa is the ratio of the dominant frequencies of P2 and A2, respectively.

Canadian consensus recommendations for the measurement and reporting of diastolic dysfunction by echocardiography: from the Investigators of Consensus on Diastolic Dysfunction by Echocardiography.

Abnormalities of diastolic filling are increasingly recognized as a cause of symptoms and predictors of outcome in patients with most forms of heart disease. Noninvasive assessment of diastolic filling is possible in almost all patients, but accurate evaluation must relate echocardiographic Doppler measurements to the complex physiologic and hemodynamic factors responsible for normal and abnormal filling. This evaluation has been facilitated by recent correlation of Doppler measurement of mitral and pulmonary venous inflow with hemodynamic studies. These studies have confirmed that when a careful, integrated approach is taken, Doppler flow patterns can document a progressive pattern of abnormality in many conditions. Impaired left ventricular (LV) relaxation is seen early and is recognized by a decrease in early transmitral LV filling and an increased proportion of filling during atrial contraction. As abnormalities progress, increasing LV chamber stiffness and elevated left atrial pressure lead to a "pseudonormal" filling pattern that previously has caused considerable confusion. This can be unmasked by careful evaluation of pulmonary venous inflow and the use of the Valsalva maneuver. When marked diastolic abnormalities are present, LV filling has restrictive features characterized by rapid early filling, a very stiff left ventricle with high filling pressures, and a poor prognosis. Routine measurement of indexes of diastolic filling have been hampered by uncertainty as to what should be measured, what techniques should be used, definition of normal values, and a clear method of reporting findings. This report represents the efforts of a Canadian consensus group to define a national standard for the performance and reporting of echocardiographic Doppler studies of diastolic filling.

Regression of left ventricular hypertrophy in patients with essential hypertension. Results of 6 month treatment with indapamide.

Left ventricular hypertrophy (LVH) is a major risk factor for cardiovascular morbidity in hypertensive patients. The effects of diuretics on LVH have raised controversies, but recent studies suggest that diuretics are able to reduce LVH in hypertensive patients, mainly through a reduction in ventricular diameter. The present multicenter open study was designed to test the effects of indapamide, a widely used nonthiazide diuretic, on LVH in patients with essential hypertension. Patients had to have mild-to-moderate essential hypertension (supine diastolic blood pressure [sDBP] 95 to 115 mm Hg) with echocardiographic evidence of LVH (left ventricular mass index [LVMI] > 130 g/m2 for men and > 110 g/m2 for women). After a 2 week placebo run-in period, eligible patients underwent a 6 month treatment with 2.5 mg indapamide daily. All echograms were performed by the same investigator before and after 6 months of indapamide. Clinical and biological acceptability and quality of life (visual analog scale) were also studied. One hundred and thirty patients were included in the study and 112 completed the trial. Indapamide induced a significant reduction i systolic and diastolic blood pressures. Indapamide induced a marked reduction in posterior wall thickness (from 12.1 +/- 2.0 to 11.2 +/- 1.6 mm) and in interventricular wall thickness (from 12.7 +/- 1.7 to 11.8 +/- 1.9 mm; each P < .001) and a slight decrease in left ventricular diameter (P = .049). This resulted in a 13% reduction in LVMI (from 161.9 +/- 37.9 to 140.7 +/- 33.8 g/m2, P < .001). Left ventricular fractional shortening remained unchanged. There was no significant relation between changes in LVMI and changes in systolic, diastolic, or mean blood pressure. No significant adverse clinical or biological effects were reported during the study. The increased score of the visual analog scale indicated that overall well-being was improved (P < .001). Our study indicates that indapamide, in addition to blood pressure control, is able to reduce LVH. This effect was achieved mainly through a reduction in wall thicknesses rather than in internal cavity diameter.

Is the heart "empty' at syncope?

Neurally-mediated syncope (NMS) is thought to be reflexly triggered by vagal cardiac ventricular afferents that are activated by impaired cardiac filling. If this hypothesis is true then maneuvers that increase venous pooling should progressively diminish cardiac volume triggering syncope once a threshold decrease in cardiac filling is reached. Beat-to-beat recordings of heart rate, blood pressure (Finapres) and stroke volume (impedance cardiograph) were made at rest and during head-up tilt (80 degrees) in twenty controls and in fourteen patients with recurrent NMS (group 1). Hemodynamic profiles of controls and group 1 were compared. In eleven additional patients with NMS (group 2) we measured cardiac chamber volume from apical two or four-chamber views or stroke volume from Doppler measurements of the left ventricular outflow tract at rest and during tilt. Baseline values and initial response to head-up tilt of controls and group 1 patients were similar. A small negative trend in blood pressure and total peripheral resistance was present for at least 250 s before the onset of syncope. Stroke volume remained stable during this presyncopal period and increased at syncope. The profile of stroke volume changes using impedance cardiography mirrored those obtained using Doppler (5 subjects). Reliable echocardiographic measurements of cardiac chamber size were obtained in five subjects and did not change during tilt, presyncope or syncope. These data show that there is no significant decrease in cardiac volume before syncope that could serve as a trigger of syncope.

The effect of prosthesis-patient mismatch on aortic bioprosthetic valve hemodynamic performance and patient clinical status.

BACKGROUND: High pressure gradients occurring through normally functioning prosthetic valves appear to be related to a mismatch between the effective orifice area of the prosthesis and the patient's body surface area. OBJECTIVE: To determine whether prosthesis-patient mismatch affects clinical and hemodynamic status, a group of patients with a bioprosthetic heart valve in the aortic position was prospectively evaluated at 6.2+/-4.4 years after implantation by transthoracic Doppler echocardiography. METHODS: Manufacturer-derived in vitro valve areas were available in 61 patients allowing classification into two subgroups, with or without mismatch, based on a valve area at implantation indexed for body surface area 0.85 cm2/m2 or less, or greater than 0.85 cm2/m2. Clinical and hemodynamic parameters evaluated at follow-up included New York Heart Association (NYHA) class distribution, mean transprosthetic gradient, prosthetic valve area and cardiac index. RESULTS: Prosthesis-patient mismatch was present in 32 of 61 patients (52%). Although NYHA class of the patients was similar in both groups, hemo-dynamic performance of the aortic bioprostheses was worse in patients with mismatch than in patients with no mismatch, as indicated by a higher mean gradient (22+/-9 versus 15+/-8 mm Hg, P=0.002) and a lower cardiac index (3.0+/-0.7 versus 3.4+/-0.7 L/min/m2, P=0.04). The prevalence and severity of intrinsic prosthetic dysfunction were similar in both groups. Despite similar NYHA functional class distribution in both groups, the occurrence of syncope, acute pulmonary edema and angina pectoris was significantly higher in patients with mismatch (50% versus 21%, P=0.017). CONCLUSIONS: Prosthesis-patient mismatch is associated with worse hemodynamic performance and higher prevalence of adverse clinical events. However, mismatch did not promote accelerated hemodynamic or structural deterioration of the bioprosthesis.

Substitution of left ventricular outflow tract diameter with prosthesis size is inadequate for calculation of the aortic prosthetic valve area by the continuity equation.

It remains uncertain whether prosthetic ring size should be used interchangeably with measured left ventricular outflow tract (LVOT) diameter in the continuity equation to estimate the aortic prosthetic valve area by transthoracic Doppler echocardiography. To determine the difference in area caused by this substitution, the area of the prosthetic valve was calculated in 143 patients with aortic bioprostheses by use of the standard continuity equation with the measured LVOT diameter (LVOT method) and then with the bioprosthetic size (size method). Compared with known in vitro prosthetic valve areas, the LVOT method (r = 0.86; standard error of the estimate +/- 0.16 cm2; p < 0.001) was more accurate than the size method (r = 0.74; standard error of the estimate +/- 0.40 cm2; p < 0.001). The prosthetic valve area estimated by the size method overestimated the area estimated by the LVOT method by an average of 15% +/- 23% (p < 0.001). This difference in area between the two methods has increased with the interval since implantation of the bioprosthesis (p = 0.01). It is concluded that prosthetic size should not be used instead of LVOT diameter during calculation of aortic prosthetic valve area. This restriction is particularly important in patients with older bioprosthesis.

A method of dynamic analysis of iodine-123-metaiodobenzylguanidine scintigrams in cardiac mechanical overload hypertrophy and failure.

Cardiac sympathetic neuronal degeneration accompanies mechanical overload heart failure. We hypothesized that sympathetic nerve and myocyte failure share a common etiology and that 123I-metaiodobenzylguanidine (MIBG) might provide a precise method of detecting failure in chronic mechanical overload. Our aim was to develop a method for the dynamic analysis of 123I-MIBG scintigrams which could yield a quantitative index of myocardial sympathetic neuronal function in this condition. We performed serial 123I-MIBG scintigraphy in 33 volunteers, 10 orthotopic cardiac transplant recipients and 26 patients with chronic mechanical overload of the left ventricle. We constructed a compartmental model in which total heart activity represents the sum of cardiac sympathetic vesicular and cytosolic pools. Patients with antecedent mechanical overload heart failure or myocardial dysfunction had accelerated myocardial egress of tracer that we ascribed to a specific impairment in vesicular storage rather than to a more rapid turnover of an intact vesicular pool.

Use of Valsalva maneuver to unmask left ventricular diastolic function abnormalities by Doppler echocardiography in patients with coronary artery disease or systemic hypertension.

It has been suggested that changes in left atrial pressure may mask or mimic left ventricular diastolic function abnormalities detected by Doppler echocardiography. The effect of the Valsalva maneuver on the transmitral flow velocity profile was therefore studied in 28 patients without evidence of coronary artery disease (group 1, mean age +/- standard deviation 50 +/- 8 years) and in 94 patients with evidence of coronary artery disease or systemic hypertension (group 2, mean age 54 +/- 10 years). At baseline, group 2 patients had higher peak late diastolic filling velocity (A), lower peak early (E) to late diastolic filling velocity (E/A) ratio and longer isovolumic relaxation time than group 1, whereas heart rate, E velocity and E deceleration time were similar in both groups. During Valsalva, both groups had similar increases in heart rate and similar decreases in E velocity but E/A ratio decreased significantly only in group 2 because of a lesser decrease in A velocity. The E/A ratio was greater than or equal to 1.0 both before and during Valsalva in all but 1 patient in group 1, whereas in group 2, 32 patients had E/A greater than or equal to 1.0 at rest and during Valsalva, 33 patients had E/A greater than or equal to 1.0 at rest but less than 1.0 both at rest and during Valsalva. Using group 1 as controls, prevalence, specificity and positive predictive value of E/A less than 1.0 in group 2 were 31, 100 and 100% at rest and 66, 96 and 98% during Valsalva.(ABSTRACT TRUNCATED AT 250 WORDS)

Technetium 99m SESTAMIBI myocardial perfusion imaging: comparison between treadmill, dipyridamole and trans-oesophageal atrial pacing "stress" tests in normal subjects.

The purpose of this study was to determine the blood clearance, myocardial uptake and heart/lung and heart/liver ratios of technetium 99m methoxyisobutylisonitrile (99mTc-SESTAMIBI) following 3 different types of cardiac stimulation in normal subjects: treadmill stress (STRESS), intravenous administration of dipyridamole (DIP) and trans-oesophageal atrial pacing (TAP). Ten normal volunteers were submitted to 3 injections of 99mTc-SESTAMIBI (10 mCi/70 kg, separated by an interval of 7 days) following STRESS (standard Bruce protocol), DIP (0.142 mg/kg.min during 4 min) and TAP procedures. Blood samples were collected from 1 to 60 min after each 99mTc-SESTAMIBI injection. Planar imaging was performed at 5, 30 and 60 min. Blood retention (percentage of injected dose at 1 min) was 56% +/- 4%, 24% +/- 4% and 38% +/- 6% for STRESS, DIP and TAP, respectively (P less than 0.001). Myocardial uptake was similar for the 3 procedures while the heart lung ratio at 60 min was 3.1 +/- 0.5, 3.8 +/- 0.6 and 3.2 +/- 0.5 for STRESS, DIP and TAP, respectively. Heart/liver ratio at 60 min was 1.9 +/- 0.5, 1.3 +/- 0.3 and 1.1 +/- 0.2 for STRESS, DIP and TAP, respectively (P less than 0.001). These results demonstrated that the 3 types of cardiac stimulation show good imaging parameters with 99mTc-SESTA-MIBI.

Validation and applications of indexed aortic prosthetic valve areas calculated by Doppler echocardiography.

Doppler echocardiographic evaluation of aortic valve prostheses is based on the use of variables heretofore validated mostly for native valves. Accordingly, this study examined the validity and relative usefulness of the Doppler valve gradient and area measurements in 31 patients (mean age 69 +/- 10 years) 20 +/- 4 months after implantation of a given type of aortic bioprosthesis ranging in size from 19 to 29 mm. Valve area data obtained with both the standard and simplified continuity equations were compared with known in vitro prosthetic valve area measurements and an excellent correlation was obtained between the standard and simplified continuity equations (r = 0.98, SEE +/- 0.07 cm2, p less than 0.0005) and between in vivo and known in vitro prosthetic valve areas (r = 0.86, SEE +/- 0.16 cm2, p less than 0.0005). Peak gradient ranged from 10.8 to 75.0 mm Hg (mean 35 +/- 16) and mean gradient from 7.6 to 43.7 mm Hg (mean 20.5 +/- 9.5). The correlations between prosthetic valve gradient and in vivo area were r = -0.53, SEE +/- 14 mm Hg and r = -0.49, SEE +/- 8.63 mm Hg for peak and mean gradient, respectively. These relations were improved by indexing valve area by body surface area. The best correlations were obtained between indexed valve area and a quadratic function of the gradient (r = -0.72, SEE +/- 11.72 mm Hg and r = -0.70, SEE +/- 7.28 mm Hg for peak and mean gradient, respectively), reflecting a curvilinear relation.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation and applications of mitral prosthetic valvular areas calculated by Doppler echocardiography.

Doppler echocardiography is used in the noninvasive evaluation of mitral valve prostheses using parameters heretofore validated primarily for native valves. Accordingly, this study was designed to examine the validity and relative usefulness of valve gradient and area measurements in a group of 26 patients (17 women, 9 men, mean age 62 +/- 8 years), 19 +/- 4 months after implantation of different sizes (25 to 31 mm) of a given type of bioprosthesis. Areas obtained with both the continuity equation, using stroke volume measured in the left ventricular outflow tract, and the pressure half-time method are compared to known prosthetic areas derived from an in vitro hydraulic model. Areas calculated by the continuity equation correlate well with in vitro areas (r = 0.82, standard error of the y estimate = 0.1 cm2, p less than 0.001), and are within the range of predicted in vitro values in 92% of cases. Areas derived by the pressure half-time method do not correlate with in vitro areas (r = 0.15, p greater than 0.3) or continuity equation areas (r = 0.23, p greater than 0.2), and are above the range of predicted values in 69% of cases. Correlations are also found between continuity equation areas and the peak and mean valvular gradients (r = 0.59, p less than 0.005 and r = -0.63, p less than 0.0005, respectively). Taking the effect of cardiac output on gradients into account results in projected relations between indexed prosthetic areas and the pressure gradients at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)