Perioperative assessment and management of patients with valvular heart disease undergoing noncardiac surgery.

Valvular heart disease in a variety of forms is not uncommon, especially among older patients undergoing noncardiac surgery, and can be associated with increased perioperative cardiac risk. Patients with aortic stenosis are at greatest risk, although other valve lesions also can pose the risk of increased perioperative morbidity. During preoperative evaluation, attention to the presence, nature and severity of valvular heart disease allows appropriate perioperative monitoring and therapy with a goal to minimize the risk of perioperative cardiac morbidity and mortality associated with noncardiac surgery. Appropriate antibiotic prophylaxis reduces the risk of infective endocarditis. Finally, some patients with valvular heart disease and all patients with a mechanical valve prosthesis require long-term anticoagulation, which must be managed during the perioperative period.

Hemodynamics and early performance of the St. Jude Medical Regent aortic valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: The St. Jude Medical (SJM) Regent heart valve is a new bileaflet prosthetic valve modified from the currently marketed SJM mechanical valve, with a modified external profile that results in a larger geometric orifice area without changing the existing design of the pivot mechanism or blood contact surface areas. The aim of the present study was to report the early hemodynamic and clinical results of an on-going multicenter trial investigating the clinical performance of the Regent mechanical aortic valve prosthesis. METHODS: The early results from 204 patients at 11 centers in North America and Europe who underwent implantation of a Regent mechanical aortic valve prosthesis are described. Clinical status was prospectively recorded, and echocardiography with Doppler performed at hospital discharge, and at two and six months and one year postoperatively. RESULTS: Follow up to date is 109.3 patient-years (average follow up 0.5+/-0.4 years per patient; range: 0 to 1.7 years). NYHA class improved for the group, and there were low rates of clinical adverse effects. Echocardiographic mean pressure gradient at six months was 13.8+/-10.3, 7.4+/-4.1, 5.4+/-3.2, 5.2+/-2.8, 3.4+/-2.3 and 3.6 mmHg, respectively, for 19, 21, 23, 25, 27 and 29 mm valves; effective orifice area was 1.5+/-0.6, 2.0+/-0.7, 2.4+/-1.0, 2.5+/-0.7, 3.6+/-1.4 and 4.8 cm2, respectively. There was a statistically significant decrease in left ventricular mass index between early postoperative (169.1+/-57.7 g/m2) and six months follow up (137.2+/-42.7 g/m2, delta = -30.1+/-42.5 g/m2, p <0.0001). CONCLUSION: The SJM Regent aortic valve has excellent associated hemodynamics with rapid and significant left ventricular mass regression. In all cases of adverse events, rates fell within Objective Performance Criteria guidelines. Long-term clinical assessment is on-going.

Eccentric mitral regurgitation jets among patients having sustained inferior wall myocardial infarction.

A strong association has been recognized between partial or complete mitral leaflet flail and highly eccentric mitral regurgitation jets. In light of anecdotal observation of eccentric mitral regurgitation apparently due to geometric and functional changes accompanying inferior wall myocardial infarction, the present study was performed to systematically study the eccentricity of mitral regurgitation jets complicating nonacute inferior wall myocardial infarction. Forty-eight consecutive patients with evidence of prior isolated inferior wall myocardial infarction and at least moderate mitral regurgitation but without other valvular, annular, chordal, or ventricular pathology potentially contributory to mitral regurgitation were studied. Mitral regurgitation jets were characterized with respect to eccentricity and anterior versus posterior direction. Regurgitant jet and mitral leaflet position were quantified relative to the mitral annulus. Five of 48 patients (10.4%) had eccentric jets, of which four were directed posterior and one anterior. Although not reaching statistical significance, patients with eccentric jets tended to have somewhat smaller left atrial size (41.2 +/- 7.8 vs 47.2 +/- 9.3 mm, P = 0.17) and left ventricular size (51.5 +/- 3.4 vs 55.1 +/- 7.8 mm, P = 0.13), and higher left ventricular ejection fraction (0.52 +/- 0.11 vs 0.46 +/- 0.09, P = 0.25) compared with patients with noneccentric jets. Leaflet position relative to the mitral annulus was significantly different among patients with eccentric compared with noneccentric posterior jets (54 +/- 10 degrees vs 33 +/- 11 degrees, P = 0.02), implying greater leaflet restriction toward the left ventricular apex. In conclusion, approximately one in 10 patients with isolated inferior wall myocardial infarction and at least moderate mitral regurgitation was found to have marked eccentricity of the regurgitant jet. Leaflet position was more apically displaced among patients with eccentric jets, suggesting greater leaflet restriction in systole. The finding of a highly eccentric posterior mitral regurgitation jet can be due to inferior wall myocardial infarction with posterior leaflet restriction as well as partial or complete anterior mitral leaflet flail.

Impact of high transvalvular to subvalvular velocity ratio early after aortic valve replacement with Freestyle stentless aortic bioprosthesis.

Although stentless aortic bioprostheses are associated in general with excellent hemodynamics, a subset of patients exhibit high early postoperative gradients. The present study was performed to evaluate the prevalence and impact of suboptimal hemodynamics early after stentless tissue aortic valve replacement. The early postoperative peak transvalvular to peak left ventricular (LV) outflow tract velocity ratio was > or = 3.0 in 44 (6.7%) of 658 patients in the multicenter, long-term study of the Freestyle stentless aortic valve. Mean gradient, effective orifice area (EOA), and LV mass index were compared between these patients and a control group of 44 patients matched for age, sex, valve size, and implant technique. High velocity ratio was associated with female sex (63.6% v 42.8%, P =.01), smaller valve size (77.3% v 45.3%, < or = 23 mm, P =.0004), and use of the modified subcoronary rather than full root implant technique (90.9% v 70.2% modified subcoronary, P =.01). Mean gradient was significantly higher (P <.05) and EOA lower (P <.05) early postoperative and throughout follow-up among patients with high velocity ratio. LV mass index decreased across time among both groups; patients with high velocity ratio tended to have higher LV mass index with less complete LV mass regression, although the difference did not reach statistical significance. In conclusion, there was a 6.7% incidence of hemodynamics suggestive of significant aortic stenosis early after implantation of a Freestyle stentless aortic valve. Gradients decreased and EOA increased in the first months after surgery, although they remained less favorable. Multiple factors likely play a role in early suboptimal hemodynamics following stentless tissue aortic valve replacement, including factors related to patient population, valve size, implant modality, and implant technique.

Echocardiographic correlates of Freestyle stentless tissue aortic valve endocarditis.

Echocardiography plays a critical role in assessing prosthetic valve endocarditis. Because normal paravalvular findings can mimic paraprosthetic infection early after implantation of a stentless bioprosthesis, we sought to define echocardiographic characteristics associated with infective endocarditis (IE) complicating stentless tissue aortic valve replacement. Between September 1992 and October 2000, 388 patients underwent aortic valve replacement with a Freestyle stentless tissue aortic valve. Nine patients presented with clinical endocarditis 10 days to 107 weeks after surgery. Patients included 8 men and 1 woman, ages 38 to 72 years. Of these, 7 patients underwent valve explantation, 1 patient was treated medically, and 1 died within hours of presentation. Intraoperative post-pump transesophageal echocardiography (TEE) and subsequent TEE examinations were reviewed for pertinent findings. For comparison, 22 patients without IE who underwent follow-up TEE within 1 year after Freestyle aortic valve replacement served as a control group. Abnormal TEE findings in patients with IE included new or worsening paravalvular aortic regurgitation (AR) in 4, diffuse leaflet thickening in 4, valvular vegetations in 1, and aorto-atrial fistula in 1. A progressive increase in the paravalvular echo-dense and/or echo-lucent space occurred in 5 of 9 patients. Among control subjects, paravalvular findings observed on immediate post-pump TEE resolved over time, and did not increase in size in any patient. In addition, no control patient developed new or progressive AR, diffuse leaflet thickening, or vegetations. TEE is useful in detecting valvular and paravalvular involvement of IE complicating stentless tissue aortic valve replacement. Because incremental change in paravalvular appearance from post-pump TEE is an important finding, intraoperative post-pump TEE should be performed and recorded in all patients undergoing stentless tissue aortic valve replacement.

Eight-year hemodynamic follow-up after aortic valve replacement with the Toronto SPV stentless aortic valve.

The hemodynamic performance of stentless aortic bioprostheses has been well described during the first few months after surgery. The purpose of the present study was to describe the hemodynamic performance of the Toronto SPV valve (St. Jude Medical, Inc, St. Paul, MN) in a multicenter trial through 8 years. The long-term study of the Toronto SPV valve includes 447 consecutive patients from 6 investigative centers. Echocardiographic follow-up was performed at specified intervals, with quantitative analysis performed at a centralized core laboratory. Mean transvalvular gradient decreased significantly between discharge and 6 months, between 6 months and 1 year, and between 1 year and 2 years after surgery, without further significant change. The effective orifice area increased significantly early after surgery and continued to increase through 6-year follow-up. The left ventricular (LV) stroke volume increased progressively from discharge through 6-year follow-up. The LV mass index decreased significantly from discharge through 3 years after surgery and stabilized through 5 years. There was a gradual increase in LV outflow tract diameter between 1 year and 6 years after surgery. The prevalence of any aortic regurgitation (AR) (including trivial) and > or = mild AR increased significantly between discharge and 6-year to 8-year follow-up. However, the prevalence of > or = moderate AR remained very low at 6 years (2.6%) and 8 years (4.5%) after surgery. In conclusion, the Toronto SPV stentless tissue aortic valve is associated with excellent hemodynamics early after surgery and through 8 years after surgery. LV mass decreases early, and returns to within the range of normal by 1 year after surgery. There is evidence of continued LV mass regression involving the LV outflow tract, potentially contributing to a small but significant late improvement in hemodynamics. The prevalence of significant AR remains low through 8 years.

Echocardiographic assessment of stentless aortic bioprosthetic valves.

Stentless tissue aortic valves are gaining in popularity because of advantages in hemodynamics and durability compared with stented bioprostheses. The absence of a rigid sewing ring and struts makes these valves pliable, and distortion at implantation can result in valve dysfunction. Because the anatomy and implantation techniques of stentless tissue valves are unlike those of mechanical and stented tissue valves, their echocardiographic appearance is unique on both intraoperative and subsequent transthoracic and transesophageal echocardiography. This report describes the echocardiographic appearance of normally functioning stentless tissue heterograft aortic valves as an aid to their intraoperative and subsequent echocardiographic assessment.

Impact of high transvalvular velocities early after implantation of Freestyle stentless aortic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Stentless aortic bioprostheses have excellent hemodynamics, although heterogeneity in gradients has been observed. The present study was intended to determine whether high early postoperative transvalvular velocities correlate with other measures of left ventricular outflow obstruction, whether the phenomenon is transient, and whether high velocities observed early after surgery predict differences in subsequent valve performance or left ventricular remodeling. METHODS: Sixty-eight consecutive patients who underwent implantation of Freestyle stentless aortic bioprosthesis and survived to hospital discharge underwent early postoperative echocardiography. Peak transvalvular velocity was used to define a 'high-velocity' group, based on mean (+ 1 SD) for the group. Mean pressure gradient, ratio of peak to proximal velocities, and effective orifice area were assessed; change in peak velocity and evidence of left ventricular mass regression were studied at one-year follow up. RESULTS: Of 68 patients, 14 (21%) had 'high velocities' based on early postoperative peak transvalvular velocity >3.0 m/s. There was a higher prevalence of women (64% versus 33%, p = 0.04), and both body surface area (1.79+/-0.17 versus 1.95+/-0.20 m2, p = 0.01) and implanted valve size (22.9+/-2.0 versus 24.9+/-2.1 mm, p = 0.003) were smaller among the 'high-velocity' group. High velocity correlated with other measures of resistance to left ventricular outflow, including higher mean gradient (20.9+/-6.5 versus 8.3 +/-4.2 mmHg, p <0.001) and lower effective orifice area (1.15+/-0.36 versus 1.69+/-0.62 cm2, p <0.001). High early postoperative velocities persisted at one year in eight of 13 (62%) patients. Left ventricular mass regression occurred less often in the 'high-velocity' group (38% versus 77% of patients, p = 0.03) and was present in only one of eight (12%) patients in whom high velocity persisted at one year. CONCLUSION: High early postoperative transvalvular velocity suggests resistance to left ventricular outflow. High velocities are transient in some patients, although persistence of high transvalvular velocity suggests 'prosthesis-patient mismatch' with incomplete relief of left ventricular outflow obstruction.

Calcification and degeneration following mitral valve reconstruction in patients requiring chronic dialysis.

BACKGROUND AND AIM OF THE STUDY: Abnormal calcium homeostasis in patients with end-stage renal failure results in dystrophic calcification; this limits the use of heterograft tissue valve prostheses in patients on chronic dialysis. Mitral valve reconstruction offers advantages over mitral replacement in many patients without renal failure, and offers theoretical advantages in patients requiring dialysis. This study was performed to determine the outcome of mitral valve reconstruction in patients with renal failure requiring chronic dialysis. METHODS: Ten patients with end-stage renal failure and on chronic dialysis who underwent mitral valve repair were identified retrospectively and followed for clinical and echocardiographic outcome. All patients had good results immediately following surgical valve mitral repair, with no more than mild mitral regurgitation and low transmitral gradients on intraoperative transesophageal echocardiography. RESULTS: Clinical and echocardiographic follow up was available for eight patients at an average of 2.3 +/- 1.4 years after surgery. Despite there being no significant valve calcification at the time of surgery, visible mitral leaflet calcification was evident in seven of these patients, and the transmitral gradient for the group was significantly increased (from 4.8 +/- 1.7 mmHg to 8.3 +/- 3.9 mmHg, p = 0.04). Two patients required reoperation for failed mitral repair; one at six months due to chordal rupture, and one at 15 months due to mitral calcification with stenosis. CONCLUSION: Despite good early surgical results, there was accelerated calcification of the repaired mitral valve, a rapid increase in postoperative mitral gradients, and a high incidence of failure of the reconstruction. Additional prospective studies are required to evaluate the optimal intervention for patients with end-stage renal failure who require mitral valve surgery.

Usefulness of hypotension during dobutamine echocardiography in predicting perioperative cardiac events.

This study was undertaken to determine the prognostic significance of hypotension induced during preoperative dobutamine stress echocardiography (DSE) before vascular and noncardiac thoracic surgery. Wall motion abnormality during DSE predicts perioperative risk. Although hypotension during DSE has not been shown to correlate with the presence or severity of coronary artery disease, its significance in perioperative risk assessment is unknown. We retrospectively studied 300 patients who had DSE within 6 months of noncardiac surgery. Perioperative events including death, myocardial infarction, ischemia, and arrhythmias were recorded. Odds ratios with 95% confidence intervals were used to examine the association between clinical and echocardiographic variables and perioperative events. A hypotensive response during DSE was seen in 85 patients (28%). Forty-eight patients (16%) had 54 perioperative complications including 4 cardiac-related deaths, 10 myocardial infarctions, 12 myocardial ischemic events, and 28 arrhythmias. Hypotension during DSE was predictive of the combined end point of perioperative cardiac mortality, myocardial infarction, and ischemia (odds ratio 4.04, 95% confidence interval 1.72 to 9.51). In a multivariate logistic regression model, hypotension during DSE remained a significant predictor (odds ratio 4.10, p<0.01). DSE-related hypotension was predictive of perioperative cardiac events and therefore may have a role in risk stratification before vascular or noncardiac thoracic surgery.

Transesophageal echocardiographic (TEE) evaluation of prosthetic valves.

TEE overcomes many of the imaging constraints associated with transthoracic echocardiography for the assessment of valvular anatomy and function. Additional imaging artifacts and constraints associated with prosthetic valves are minimized or overcome with TEE. As such, TEE allows assessment of prosthetic valve anatomy and function and paraprosthetic anatomy, and serves as the diagnostic imaging modality of choice for patients with suspected prosthesis dysfunction or endocarditis.

Diagnostic value of resting tricuspid regurgitation velocity and right ventricular ejection flow parameters for the detection of exercise induced pulmonary arterial hypertension.

UNLABELLED: Our objectives were to evaluate resting tricuspid regurgitation velocity (TRV) and right ventricular outflow tract velocity curve (RVOTvc) profiles as markers for development of exercise induced pulmonary arterial hypertension (ExPHT). ExPHT is an elusive cause of dyspnea and fatigue. When present, Doppler echocardiography can detect and quantify elevated pulmonary pressure. However, the characteristics and diagnostic value of resting TRV and RVOTvc indices in patients with ExPHT have not been fully addressed. The study population consisted of 52 subjects (mean age 40.5 +/- 10.9, range 22-68 years) and was divided into three subsets as follows: 1. Patients (n = 22) with overt pulmonary hypertension (PHT), 2. Patients (n = 8) with ExPHT, 3. Healthy, asymptomatic volunteers (n = 22). RVOTvc indices included: Mean and peak velocity, systolic velocity time integral (VTI); velocity time integral at peak velocity (VTImax), acceleration time; ejection time. TRV was used as an index of pulmonary artery systolic pressure. There were significant differences between normals and ExPHT for TRV, acceleration time, VTI(Vmax). TRV and VTImax were predictive of EXPHT in a logistic regression model. CONCLUSION: (1) Patients with ExPHT have distinct Doppler velocity patterns suggesting the presence of a compromised pulmonary vascular bed even with normal pulmonary pressure at rest. (2) TRV and RVOTvc indices have potential diagnostic value in the early detection of ExPHT.

Echocardiographic predictors of an adverse response to a nifedipine trial in primary pulmonary hypertension: diminished left ventricular size and leftward ventricular septal bowing.

BACKGROUND: The clinical course in primary pulmonary hypertension (PPH) is improved by calcium channel blocker therapy in those with a favorable hemodynamic response during a trial of high-dose oral nifedipine. Although trials of nifedipine are performed only in patients who demonstrate pulmonary vasodilator reserve to short-acting agents, this response does not predict the safety of nifedipine treatment, which can result in severe first-dose hypotension and death. STUDY OBJECTIVES: To identify echocardiographic parameters that predict first-dose nifedipine-induced hypotension in patients with PPH. METHODS: The pretrial echocardiograms of 23 consecutive PPH patients (mean age, 42.3 +/- 13 years; 77% female) undergoing evaluation of pulmonary vasodilator reserve with nifedipine were analyzed. Patients were classified as those who suffered first-dose nifedipine hypotension (group 1) and those who did not (group 2). Echocardiographic measures of chamber size and septal geometry in the two groups were compared. RESULTS: Five measures reflecting diminished left ventricular (LV) size and leftward ventricular septal bowing were found to be associated with nifedipine hypotension: LV transverse diameter in systole (LVDs; p = 0.007), LV transverse diameter in diastole (LVDd; p = 0.05), LV area in systole (LVAs; p = 0.009), LV area in diastole (LVAd; p = 0.03), the ratio of RV to LVAs (p = 0. 02), and leftward ventricular septal bowing (p = 0.01). The LV dimensions found to best predict nifedipine-induced hypotension were LVDs < 2.7 cm, LVDd < 4.0 cm, LVAs < 15.5 cm(2), and LVAd < 20.0 cm(2). CONCLUSIONS: Readily available echocardiographic parameters in patients with PPH are predictive of nifedipine-induced hypotension, and can be used to select patients in whom a trial of nifedipine should be avoided.

Dobutamine stress echocardiography for the preoperative evaluation of patients undergoing lung volume reduction surgery.

BACKGROUND: Lung volume reduction surgery has been proposed as a bridge to lung transplantation and as definitive therapy for advanced chronic obstructive lung disease. However, patient selection criteria and optimal preoperative assessment have not been clearly defined. OBJECTIVE: We investigated the feasibility, safety, and value of dobutamine stress echocardiography as a predictor of major early cardiac events in patients who underwent lung volume reduction surgery. METHODS: The study population consisted of 46 patients (21 men and 25 women, mean age 59 +/- 9 years) who underwent dobutamine stress echocardiography (maximum dose 40 microg. kg(-1). min(-1) plus atropine if needed) 180 days or less before lung volume reduction surgery. Adverse cardiac events were prospectively defined and tabulated during hospitalization after the operation and at subsequent outpatient visits. RESULTS: Dobutamine stress echocardiography was interpretable in 45 of 46 (98%) patients. There were no adverse events during testing. The studies revealed normal left ventricular systolic function at rest in all patients and normal right ventricular function in all patients but one. Thirteen patients had right ventricular enlargement. Estimated right ventricular systolic pressure was mildly elevated (>40 mm Hg) in 5 patients. Four patients (9%) had stress tests positive for ischemia. There were no perioperative deaths. Follow-up was available for 44 of 45 patients at a duration of 20.0 +/- 7.0 months. Two major adverse cardiac events occurred in the same patient in whom the results of dobutamine stress echocardiography were positive for ischemia (positive predictive value 25%, 95% confidence interval 0% to 83%; negative predictive value 100%, 95% confidence interval 90 to 100%). CONCLUSION: Despite end-stage chronic obstructive lung disease and poor ultrasound windows, dobutamine stress echocardiography is feasible and safe in patients undergoing evaluation for lung volume reduction surgery. It yields important information on right and left ventricular function and has an excellent negative predictive value for early and late adverse cardiac events.

Adherence of albunex to an apical left ventricular thrombus.

A previously unrecognized left ventricular thrombus developed a distinct echogenic rim after intravenous injection of albumin microbubbles despite no visible opacification of the left-sided chambers. Absence of visible left ventricular opacification suggests a low density of microbubbles crossing the pulmonary vasculature and a high affinity of the microbubbles for the thrombus or its endothelial surface. These findings support previous observations that albumin microbubbles demonstrate transient adherence to abnormal endothelium.

Echocardiographic features of primary pulmonary hypertension.

Primary pulmonary hypertension (PPH) is essentially a diagnosis of exclusion and usually is made late because of the nonspecific nature of the early signs and symptoms. Echocardiography is a key screening test in the diagnostic algorithm of patients with suspected PPH. The purpose of this study was to define the echocardiographic Doppler features in patients with PPH at the time of diagnosis. From 1992 to 1997, 51 patients were diagnosed with PPH at our institution. All underwent a standardized transthoracic echocardiographic examination, including a contrast study and transthoracic echocardiographic examination if indicated. Pulmonary artery systolic pressure was calculated from the tricuspid regurgitation jet. The majority of patients had pulmonary artery systolic pressure greater than 60 mm Hg (96%) associated with systolic flattening of the interventricular septum (90%), enlarged right atrium (92%) and ventricle (98%), and reduced right ventricular systolic function (76%). There was an increase in the interventricular septal thickness (>1.2 cm) in 21 (43%) of 49 patients, accompanied by a septal/posterior wall ratio greater than 1.3 in 11 (22%) of 49. Although a reduction in both left ventricular systolic and diastolic volumes was noted, global left ventricular systolic function was preserved in all patients. Mitral E/A ratio was less than 0.7 in 7 (22%) patients studied. Color Doppler revealed moderate to severe tricuspid regurgitation and pulmonic insufficiency in 41 (80%) of 51 and 16 (31%) of 51 of cases, respectively. Pericardial effusion (7 small and 1 moderate) and patent foramen ovale (n = 12) were also frequently detected. At the time of initial diagnosis, PPH is associated with secondary cardiac abnormalities in the majority of patients.

Absence of cardiac valve dysfunction in obese patients treated with sibutramine.

OBJECTIVE: Serotonin-releasing agents prescribed as weight-loss medications have been implicated as a cause of acquired aortic and mitral valve abnormalities. Sibutramine hydrochloride (MERIDIA) is a serotonin and norepinephrine reuptake inhibitor with proven efficacy of weight reduction. The purpose of this study was to determine the incidence of cardiac valve disease in sibutraminetreated patients. RESEARCH METHODS AND PROCEDURES: Obese patients with type 2 diabetes mellitus enrolled in an ongoing double-blind, placebo-controlled, parallel-arm, 12-month study of sibutramine (followed by a 12-month open label extension) underwent transthoracic echocardiographic imaging and color Doppler interrogation for assessment of cardiac valve anatomy and function. RESULTS: A total of 210 patients were evaluated. Of these, 133 were receiving sibutramine (72 in the double-blind period), and 77 were receiving placebo. The mean+/-Standard Deviation age was 54+/-9 years, and the mean duration of treatment was 229+/-117 days (approximately 7.6 months). The prevalence of left-sided cardiac valve dysfunction was low and similar for the two treatment groups (sibutramine 3/133, or 2.3%; placebo 2/77, or 2.6%). All five cases were cases of aortic insufficiency; four were mild, one was severe (in a placebo patient). All three sibutramine cases were patients over age 50; two had a history of systemic hypertension. CONCLUSION: The prevalence of left-sided cardiac valve dysfunction was not higher than background in obese patients treated with sibutramine for an average of 7.6 months.

Preserved diagnostic utility of dobutamine stress echocardiography in pacemaker-dependent patients with absolute chronotropic incompetence.

BACKGROUND: The mechanism by which dobutamine induces ischemia is thought to depend on both increased chronotropy and inotropy. No data have been reported on the diagnostic power of dobutamine stress echocardiography (DSE) among patients with fixed-rate pacemakers and absolute chronotropic incompetence. The purpose of this study was to determine the diagnostic and prognostic utility of DSE in patients with fixed-rate, demand ventricular pacing who had no heart rate (HR) increase during DSE. METHODS: From 1990 to 1997, 22 patients remained pacemaker dependent with a fixed HR (69.7 +/- 5.7 beats/min) throughout DSE. Myocardial perfusion single-photon emission computed tomography and coronary angiographic studies were reviewed when available. Clinical follow-up was determined for all patients at 15.4 +/- 7.7 months. RESULTS: In spite of absolute chronotropic incompetence during DSE, 11 (50%) of 22 patients had test results consistent with inducible ischemia. Coronary artery disease was confirmed in 6 (75%) of 8 who had coronary angiograms. Three of 11 patients with negative DSE underwent coronary angiography that confirmed the absence of significant coronary artery disease. DSE had a sensitivity of 100% and specificity of 60% in pacemaker-dependent patients with absolute chronotropic incompetence. At the time of clinical follow-up, none of the patients with no inducible ischemia on DSE had an adverse ischemic cardiac event. CONCLUSIONS: This study suggests that DSE has preserved diagnostic and prognostic utility in pacemaker-dependent patients with absolute chronotropic incompetence.

Effect of pharmaceutical services on adherence to criteria-for-use guidelines in the operating room.

Guidelines for the use of neuromuscular blocking agents (NMBAs) and sedatives during two- to four-hour surgical procedures were developed, and the effect of pharmacy presence on adherence to the guidelines was determined. Differences in cost per dose of the NMBAs pancuronium bromide, cisatracurium besylate, and vecuronium bromide were determined. Pancuronium was designated as the first-line agent in the NMBA guidelines, cisatracurium as the second-line agent, and vecuronium as the third-line agent. In the sedative guidelines, lorazepam was the first-line agent, midazolam was the second-line agent, and propofol was the third-line agent. Pharmacy presence in the operating room was provided during January 1997. The pharmacist made a preliminary decision about the most appropriate agent and encouraged guideline adherence. Cost and adherence data were compared with data for November 1996 and March 1997. During January, the NMBA guidelines were followed 75% of the time and the sedative guidelines were followed 15% of the time; the corresponding rates for March were 40% and 12%. Compared with November 1996, a saving of $5.61 per case was observed in January in the NMBA category and a saving of $2.77 was observed in March; between January and March, there was an increase of $2.84 per case. Pharmacy presence in the OR was associated with better adherence to criteria-for-use guidelines for NMBAs and sedatives; NMBA cost savings associated with implementation of the guidelines were higher when a pharmacist was present.