Impact of left ventricular function on immediate and long-term outcomes after pericardiectomy in constrictive pericarditis.

OBJECTIVE: Most patients with constrictive pericarditis have normal measures of left ventricular function when assessed by the ejection phase index of ejection fraction, yet there is a wide spectrum of outcome after pericardiectomy. We hypothesized that parameters of non-ejection indexes of cardiac function (+dP/dt and tau) may predict postoperative prognosis. METHODS: The immediate and long-term outcomes of pericardiectomy were analyzed in 40 patients (30 male, mean age 62 years) with surgically confirmed constrictive pericarditis who underwent preoperative cardiac catheterization using high-fidelity micromanometer pressures. Left ventricular pressures were digitized at 5-msec intervals during end expiration, from which peak positive dp/dt and tau measurements were obtained. Patients were classified into 3 groups: Group 1 (n = 13) included those with abnormal +dP/dt and tau (defined as +dP/dt < 1200 mm Hg/s, tau > 50 msec); group 2 (n = 11) included those with either abnormal +dP/dt or tau; and group 3 (n = 16) included those with normal +dP/dt and tau. RESULTS: There were no significant differences of gender, New York Heart Association class, duration of symptoms, and underlying cause among the 3 groups. Group 1 patients had lower preoperative ejection fraction and higher left and right ventricular end-diastolic pressures. Postoperative inotropic support was more frequently needed in group 1, and postoperative mortality was higher in group 1 than in groups 2 and 3. All postoperative deaths but 1 were in group 1. The median postoperative follow-up was 2.4 years. The postoperative long-term survival of group 1 was significantly lower compared with that of groups 2 and 3. CONCLUSION: In patients with constrictive pericarditis undergoing pericardiectomy, those with abnormal left ventricular contractility and relaxation properties assessed by cardiac catheterization before surgery incur higher operative mortality and poor long-term outcome after surgery.

Physiological assessment of coronary artery disease in the cardiac catheterization laboratory: a scientific statement from the American Heart Association Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology.

With advances in technology, the physiological assessment of coronary artery disease in patients in the catheterization laboratory has become increasingly important in both clinical and research applications, but this assessment has evolved without standard nomenclature or techniques of data acquisition and measurement. Some questions regarding the interpretation, application, and outcome related to the results also remain unanswered. Accordingly, this consensus statement was designed to provide the background and evidence about physiological measurements and to describe standard methods for data acquisition and interpretation. The most common uses and support data from numerous clinical studies for the physiological assessment of coronary artery disease in the cardiac catheterization laboratory are reviewed. The goal of this statement is to provide a logical approach to the use of coronary physiological measurements in the catheterization lab to assist both clinicians and investigators in improving patient care.

Doppler echocardiographic evaluation of pulmonary regurgitation facilitates the diagnosis of constrictive pericarditis.

Diagnosing constrictive pericarditis (CP) remains a clinical challenge. Ventricular interdependence and dissociation of intrathoracic and intracardiac pressures are hallmark features that are readily recognized by invasive and noninvasive hemodynamics. The Doppler echocardiographic signal from pulmonic valve regurgitation depends on the relationship between pulmonary artery (intrathoracic) and right ventricular (intracardiac) pressure. Respiration-associated changes in this signal may aid in the evaluation of pericardial constriction. We demonstrate here that early diastolic cessation with inspiration can indicate a CP process. Early diastolic cessation with inspiration was shown to have correctly diagnosed CP in 70% of the patients in this study, with a sensitivity of 77%, specificity of 64%, positive predictive value of 67%, and negative predictive value of 75%. This noninvasive insight into dissociation of intracardiac and intrathoracic pressures, although not sufficient on its own, may be a valuable tool for aiding in the diagnosis of CP.

Effect of lesion length on fractional flow reserve in intermediate coronary lesions.

BACKGROUND: Fractional flow reserve (FFR) has become a gold standard in physiological assessment of coronary artery stenosis. An FFR < 0.75 is considered as a reliable physiological parameter indicating functionally significant lesion. Lesion length (LL) may affect the translesional hemodynamics. However, the effect of LL on FFR has not been adequately assessed. We sought to evaluate the effect of LL on FFR in patients with angiographically intermediate coronary artery disease. METHODS: We performed FFR measurements by pressure guidewire in 63 intermediate-grade lesions (63 patients) by visual assessment. Lesion length and percent diameter stenosis (%DS) at the lesion site were determined by performing off-line quantitative coronary angiography analysis. RESULTS: Overall, there was a moderate inverse correlation between FFR and %DS (r = -0.55, P < .001). In addition, there was a weak inverse correlation between LL and FFR (r = -0.31, P < .001). Using a receiver operating characteristic curve analysis, an LL > or = 10 mm was identified as the best cutoff value for predicting an FFR < 0.75 (sensitivity 95%, specificity 66%, positive predictive power 48%, and negative predictive power 97%). The correlation between FFR and %DS was significantly improved for LL > or = 10 mm, as compared with LL < 10 mm (r = -0.78, P < .001; r = 0.16, P = NS; respectively). Similar improvement with LL was also observed for intermediate lesions by quantitative coronary angiography (%DS 50%-70%; r = 0.19, P = NS for LL < 10 mm; r = -0.74, P < .001 for LL > or = 10 mm). CONCLUSIONS: This study demonstrates that LL differentially affects the correlation between the functional assessment (FFR) and the "anatomic" severity (%DS) of coronary lesions and suggests that LL has a significant impact on the physiological significance of intermediate-grade coronary lesions.

A curricular initiative for internal medicine residents to enhance proficiency in internal jugular central venous line placement.

OBJECTIVE: To determine the feasibility, efficacy, and outcomes of teaching Internal Jugular (IJ) central venous line placement (CVLP) to internal medicine residents in a hands-on training experience with adult patients. SUBJECTS AND METHODS: Data were obtained from 47 residents during their 3-year residency program through questionnaires and a proprietary system that tracks resident procedures. Twenty-five postgraduate year (PGY) 2 residents at the Mayo Clinic in Rochester, Minn, were assigned to IJ-CVLP training in the cardiac catheterization laboratory from January 2001 to June 2001. Their experience, analyzed immediately after training and at completion of residency, was compared with that of 22 PGY-2 residents in the same class who were not assigned to IJ-CVLP training. RESULTS: The median Likert scores of the residents' self-reported perception of independence in IJ-CVLP increased from 3.0 (mean +/- SD score, 2.8+/-1.4) before the intervention to 5.0 (4.4+/-0.9) after the intervention (P<.001, signed rank test). At graduation, trained residents had performed more IJ-CVLPs than the control residents (mean +/- SD, 17.8+/-8.4 vs 9.8+/-6.3, respectively; P<.001). Residents who received IJ-CVLP training, compared with those who did not, showed a significant increase in the mean percentage of IJ-CVLPs performed independently between PGY-1 (2.2%) and PGY-3 (31.2%) (P=.008). CONCLUSIONS: Training internal medicine residents to perform IJ-CVLP is feasible in the cardiac catheterization laboratory with supervision from an attending cardiologist. Trained residents performed significantly more IJ-CVLPs independently during their third year compared with their first year of training. We believe this initiative may be implemented successfully in graduate medical education curriculums.

Intravascular ultrasound-guided treatment for angiographically indeterminate left main coronary artery disease: a long-term follow-up study.

OBJECTIVES: The purpose of this study was to evaluate the efficacy of an intravascular ultrasound (IVUS)-guided strategy for patients with angiographically indeterminate left main coronary artery (LMCA) disease. BACKGROUND: The assessment of LMCA lesions using coronary angiography is often challenging; IVUS provides useful information for assessment of coronary disease. METHODS: Intravascular ultrasound was performed on 121 patients with angiographically normal LMCAs to determine the lower range of normal minimum lumen area (MLA), defined as the mean - 2 SD. We conducted IVUS studies on 214 patients with angiographically indeterminate LMCA lesions, and deferral of revascularization was recommended when the MLA was larger than this predetermined value. RESULTS: The lower range of normal LMCA MLA was 7.5 mm(2). Of the patients with angiographically indeterminate LMCAs, 83 (38.8%) had an MLA <7.5 mm(2), and 131 (61.2%) an MLA > or =7.5 mm(2). Left main coronary artery revascularization was performed in 85.5% (71 of 83) of patients with an MLA <7.5 mm(2) and deferred in 86.9% (114 of 131) of patients with an MLA > or =7.5 mm(2). Long-term follow-up (mean 3.3 +/- 2.0 years) showed no significant difference in major adverse cardiac events (target vessel revascularization, acute myocardial infarction, and death) between patients with an MLA <7.5 mm(2) who underwent revascularization and those with an MLA > or =7.5 mm(2) deferred for revascularization (p = 0.28). Based on outcome, the best cut-off MLA by receiver operating characteristic was 9.6 mm(2). Multivariate predictors of cardiac events were age, smoking, and number of non-LMCA vessels diseased. CONCLUSIONS: Intravascular ultrasound is an accurate method to assess angiographically indeterminate lesions of the LMCA. Furthermore, deferring revascularization for patients with a minimum lumen area > or =7.5 mm(2) appears to be safe.

Effect of long-term hormone replacement therapy on coronary endothelial function in postmenopausal women.

OBJECTIVES: To determine the difference in endothelial function between premenopausal and postmenopausal women and to determine whether hormone replacement therapy (HRT) is associated with an improvement in coronary endothelial function. PATIENTS AND METHODS: Women undergoing coronary physiology studies for chest pain at the Mayo Clinic In Rochester, Minn, between December 1992 and April 2002 underwent assessment of coronary endothelium-independent and -dependent function with intracoronary administration of adenosine and acetylcholine, respectively. The coronary diameters, coronary blood flows, and coronary velocity reserves were measured. RESULTS: A total of 270 women (89 premenopausal and 181 postmenopausal) participated in the study. Endothelium-dependent coronary blood flow change (baseline to peak flow) in response to acetylcholine (10(-4), 10(-5), and 10(-4) mol/L) was lower in postmenopausal women compared with premenopausal women (39.7% vs 72.9%, P = .03). There was no significant difference between the postmenopausal women receiving and not receiving HRT with regard to percent change in coronary diameter (-21.8% vs -13.9%, P = .15), percent change in coronary blood flow (37.3% vs 42.7%, P = .74), or coronary velocity reserve (2.7 vs 2.7, P = .82). CONCLUSION: This study shows that the postmenopausal state is associated with a greater abnormality in coronary endothelial function at the level of the microcirculation. Moreover, HRT status was not associated with an improvement in coronary endothelial function in postmenopausal women.

Noninvasive identification of patients with early coronary atherosclerosis by assessment of digital reactive hyperemia.

OBJECTIVES: We investigated the value of reactive hyperemia peripheral arterial tonometry (RH-PAT) as a noninvasive tool to identify individuals with coronary microvascular endothelial dysfunction. BACKGROUND: Coronary endothelial dysfunction, a systemic disorder, represents an early stage of atherosclerosis; RH-PAT is a technique to assess peripheral microvascular endothelial function. METHODS: Using RH-PAT, digital pulse volume changes during reactive hyperemia were assessed in 94 patients without obstructive coronary artery disease and either normal (n = 39) or abnormal (n = 55) coronary microvascular endothelial function; RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at baseline. RESULTS: Average RH-PAT index was lower in patients with coronary endothelial dysfunction compared with those with normal coronary endothelial function (1.27 +/- 0.05 vs. 1.78 +/- 0.08: p < 0.001). An RH-PAT index <1.35 was found to have a sensitivity of 80% and a specificity of 85% to identify patients with coronary endothelial dysfunction. CONCLUSIONS: Digital hyperemic response, as measured by RH-PAT, is attenuated in patients with coronary microvascular endothelial dysfunction, suggesting a role for RH-PAT as a noninvasive test to identify patients with this disorder.

Myocardial bridging is associated with alteration in coronary vasoreactivity.

BACKGROUND: Shear stress alteration has been recognized as a predisposing factor for the impairment of endothelial function. Myocardial bridging is a congenital condition associated with alteration in shear stress, however, its impact upon vasoreactivity remains undetermined. METHODS AND RESULTS: This was a case-control designed study with 29 patients with myocardial bridging and 58 patients without myocardial bridging. Endothelium-dependent and endothelium-independent changes in coronary artery diameters, blood flow and wall shear stress were determined after intracoronary infusion of acetylcholine (ACH, 10(-6)-10(-4) mol/L) and nitroglycerine (NTG, 200 microg). Coronary flow velocity reserve (CFVR) was determined after intracoronary injection of adenosine (18-36 microg). In response to ACH, there was more epicardial vasoconstriction at the myocardial bridging site compared with the proximal and distal segments (-29.6+/-21.7 vs. -9.6+/-22.5 and -17.4+/-21.5%, p<0.05) and compared with the control group (-29.6+/-21.7 vs. -5.9+/-36.5%, p<0.001). The response to NTG and CFVR was the same in the case and the control group. Wall shear rate (WSR) was higher in the MB site at baseline and in response to ACH. CONCLUSIONS: MB is characterised by enhanced WSR and impairment in endothelium-dependent vasorelaxation. These functional alterations may add to the severity of structural lumen compression and thus to the clinical presentation of this congenital abnormality.

Coronary hemodynamics in patients with symptomatic hypertrophic cardiomyopathy.

The purpose of this study was to analyze coronary hemodynamics and determine a possible mechanism for microvascular dysfunction in patients with symptomatic hypertrophic cardiomyopathy (HC). Although patients with HC have been shown to have microvascular dysfunction and reduced coronary flow reserve (CFR), the mechanism by which this occurs is not well understood. We studied coronary hemodynamics in 8 patients with symptomatic HC and compared them with 8 matched controls. Compared with controls, patients with HC had higher coronary blood flow, lower coronary resistance, and lower CFR. Patients with HC also had abnormal phasic coronary flow characteristics. These results suggest that the reduction of CFR in patients with HC may be secondary to near maximal vasodilation of the microcirculation in the basal state.

Comparison of combination therapy of adenosine and nitroprusside with adenosine alone in the treatment of angiographic no-reflow phenomenon.

We sought to compare the combination therapy of adenosine and nitroprusside in no-reflow phenomenon during percutaneous coronary intervention. Improvement in coronary flow from no-reflow to postdrug state was evaluated. Patients who received adenosine (n = 21) were compared to ones who received the combination of adenosine and nitroprusside (n = 20) for treatment. Improvement of TIMI flow grades was higher in the group that received combined therapy (1.5 +/- 1.0 vs. 0.8 +/- 0.6; P < 0.05). Combination therapy of adenosine and nitroprusside is safe and provides better improvement in coronary flow compared to intracoronary adenosine alone in case of impaired flow during coronary interventions.

Pulse transmission coefficient: a nonhyperemic index for physiologic assessment of procedural success following percutaneous coronary interventions.

Intracoronary pressure measurements and the determination of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) predict adverse events. Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a high-frequency filter. The pulse transmission coefficient (PTC) is a nonhyperemic parameter that calculates the transmission of high-frequency components of the pressure signal through a stenosis. It was shown recently that PTC is highly correlated with FFR. This study was designed to examine the change of PTC as compared to FFR following PCI. Pressure signals were obtained by pressure guidewire in 27 lesions pre- and post-PCI and were analyzed with an algorithm that identifies the high-frequency component in the pressure signal. The PTC was calculated at baseline as the ratio between distal and proximal high-frequency components of the pressure waveform across the lesion. FFR measurements were assessed with intracoronary adenosine. There was a significant increase in PTC following PCI (0.15 +/- 0.17 at baseline vs. 0.84 +/- 0.11 post-PCI; P < 0.001). Comparable changes were observed for FFR (0.58 +/- 0.12 at baseline vs. 0.91 +/- 0.05 post-PCI; P < 0.001). PTC is a nonhyperemic parameter for physiologic assessment of coronary artery stenoses. Similar to FFR, PTC is significantly increased following PCI. Thus, it may serve as an adjunct index for the functional assessment of procedural success following PCI.

Abnormal coronary microvascular endothelial function in humans with asymptomatic left ventricular dysfunction.

BACKGROUND: Coronary endothelial dysfunction may potentially lead to myocardial ischemia and to the progression of heart failure. Though endothelial dysfunction is associated with advanced heart failure in humans, relatively little is known regarding their temporal relationship. Thus, the current study was designed to test the hypothesis that coronary endothelial dysfunction is present in patients with asymptomatic left ventricular dysfunction. METHODS AND RESULTS: Three hundred patients without symptoms of heart failure, with normal or mildly diseased coronary arteries at angiography underwent coronary vascular reactivity evaluation using intracoronary adenosine, acetylcholine (ACH) and nitroglycerin. Patients were divided into 2 groups based on the left ventricular ejection fraction (EF): patients with asymptomatic left ventricular dysfunction (ALVD), EF <45% (n = 11); and patients with EF > or =45% (n = 289, controls). Except for a lower high-density lipoprotein level in patients with ALVD, there were no significant differences between the groups in regards to conventional cardiovascular risk factors. There was no difference in the change (mean +/- SE) in epicardial diameter in response to ACH (-21.7% +/- 7.2% vs -13.8% +/- 1.5%, P =.3). The change in coronary blood flow in response to ACH was significantly attenuated in the patients with ALVD when compared to the controls (-18.5% +/- 14.9% vs 74.0% +/- 7.2%, P <.013). By multivariate analysis, EF was an independent predictor of coronary microvascular dilation with ACH (P <.001). CONCLUSION: The current study demonstrates that coronary microvascular endothelial dysfunction is present in ALVD. Thus, coronary endothelial dysfunction may be an early event in the pathophysiology of heart failure.

Coronary endothelial dysfunction is associated with an increased risk of cerebrovascular events.

BACKGROUND: Stroke, mainly attributable to atherothrombotic disease, represents a leading cause of disability and death in the Western world. Endothelial dysfunction, which is considered a key factor in atherogenesis, is associated with an increased risk of cardiovascular events. However, the magnitude of the association between coronary endothelial dysfunction (CED) and cerebrovascular events is unknown. This study was performed to investigate the association between CED and cerebrovascular events. METHODS AND RESULTS: We studied 503 patients without obstructive coronary artery disease (CAD) who underwent coronary endothelial function testing by intracoronary acetylcholine infusion. Patients were divided according to the presence (n=305) or absence (n=198) of CED, and medical records were examined for the occurrence of ischemic or hemorrhagic stroke or transient ischemic attack either before (prevalent) or after (incident) coronary endothelial function testing. Among the study population, a total of 25 cerebrovascular events were documented, 22 in patients with CED (15 prevalent) and 3 in patients without (all prevalent) (P=0.008). Multivariable logistic regression, which included traditional cerebrovascular disease-related risk factors, identified the presence of CED as the single strongest factor associated with cerebrovascular events (OR, 4.32; 95% CI, 1.26 to 14.83). Kaplan-Meier analysis indicated that patients with CED had a significantly higher cumulative cerebrovascular event rate than those without (P=0.04). CONCLUSIONS: Presence of CED in patients without obstructive CAD is independently associated with an increased risk of cerebrovascular events. Thus, detection of this early stage of atherosclerosis may provide important information to identify patients who benefit from aggressive preventive strategies.

Enhanced external counterpulsation improves endothelial function in patients with symptomatic coronary artery disease.

OBJECTIVES: The goal of this study was to examine the effect of enhanced external counterpulsation (EECP) on endothelial function. BACKGROUND: Enhanced external counterpulsation improves symptoms and exercise tolerance in patients with symptomatic coronary artery disease (CAD). However, the exact mechanisms by which this technique exerts its clinical benefit are unclear. METHODS: Reactive hyperemia-peripheral arterial tonometry (RH-PAT), a noninvasive method to assess peripheral endothelial function by measuring reactive hyperemic response in the finger, was performed in 23 patients with refractory angina undergoing a 35-h course of EECP. In each patient RH-PAT measurements were performed before and after the first, at midcourse, and the last EECP session. In addition, RH-PAT response was assessed one month after completion of EECP therapy; RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at rest. RESULTS: Enhanced external counterpulsation led to symptomatic improvement (>/=1 Canadian Cardiovascular Society class) in 17 (74%) patients; EECP was associated with a significant immediate increase in average RH-PAT index after each treatment (p < 0.05). In addition, average RH-PAT index at one-month follow-up was significantly higher than that before EECP therapy (p < 0.05). When patients were divided by their clinical response, RH-PAT index at one-month follow-up increased only in those patients who experienced clinical benefit. CONCLUSIONS: Enhanced external counterpulsation enhances peripheral endothelial function with beneficial effects persisting at one-month follow-up in patients with a positive clinical response. This suggests that improvement in endothelial function may contribute to the clinical benefit of EECP in patients with symptomatic CAD.

Low-output, low-gradient aortic stenosis in patients with depressed left ventricular systolic function: the clinical utility of the dobutamine challenge in the catheterization laboratory.

BACKGROUND: Although aortic valve replacement can be performed at an acceptable risk level in selected patients with left ventricular systolic dysfunction and low-output, low-gradient aortic stenosis, not all patients presenting with these hemodynamics will benefit from the operation. Some patients may have only mild aortic stenosis, despite a small calculated valve area. We report on the clinical utility of diagnostic dobutamine stimulation during cardiac catheterization in these diagnostically challenging patients. METHODS AND RESULTS: Thirty-two patients with low-output, low-gradient aortic stenosis and an ejection fraction <40% had dobutamine infusion in the catheterization laboratory. On the basis of the results of the dobutamine test, 21 patients underwent aortic valve replacement. All patients with a final aortic valve area < or =1.2 cm2 at peak dobutamine infusion and a mean gradient of >30 mm Hg were found to have severe calcific aortic stenosis at operation. In the 15 patients in whom contractile reserve was identified during dobutamine challenge (increase in stroke volume >20%), 1 patient died perioperatively (7% mortality) and 12 patients were alive in New York Heart Association class I or II status at follow-up. CONCLUSIONS: In patients with left ventricular systolic dysfunction and aortic stenosis with a low output and a low mean gradient, dobutamine challenge may aid in selecting those who would benefit from an aortic valve operation.