Prediction of perioperative risk: the glass may be three-quarters full.
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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.
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.
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.
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.
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.
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.
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.
OBJECTIVES: The aim of this study was to explore the full range of tricuspid valve regurgitation velocity (TRV) at rest and with exercise in disease free individuals. Additionally we examined the relationship of stroke volume (SV), cardiac output (CO) and TRV to exercise capacity. BACKGROUND: Doppler evaluation of TRV can be used to estimate pulmonary artery systolic pressure (PASP). Most studies have assumed TRV < or = 2.5 m/s as the upper limits of normal. The full range of TRV with exercise has been incompletely defined. METHODS: Highly conditioned athletes (n = 26) and healthy, active, young male volunteers (n = 14) underwent standardized recumbent bicycle exercise. Exercise parameters included: TRV, SV, CO, systolic (SBP) and diastolic (DBP) systemic blood pressure. RESULTS: Tricuspid valve regurgitation, SV, HR and CO were significantly higher in athletes than in nonathletes over all workloads, including rest. Systolic blood pressure and DBP did not show significant differences between the two groups. CONCLUSIONS: This study defines the upper physiologic limits of TRV at rest and during exercise in normals and provides a noninvasive standard for the diagnosis of pulmonary hypertension.
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.
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.
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.
The use of xenograft stentless tissue valves has increased because of excellent hemodynamics and availability. This article describes the impact of the incorporation of this new technology into a single institutional practice over time. A time span for continual usage of the new stentless Freestyle valve was divided into four distinct chronological groups and evaluated. Data on 266 consecutive patients receiving the Freestyle prosthesis were analyzed with regard to demographics, degree of illness, complexity of surgery, and outcomes to discover any distinct changes over time with respect to experience and acquired confidence and surgical expertise. Findings among the four groups were compared using Student's t-test. The only change in patient demographics was younger age (mean age decreased from 70 to 62 years). The number of procedures rose steadily, and the degree of illness increased as noted in the increase between groups in the percentage of patients with comorbidities (from 45% to 92%). The complexity of surgery score steadily increased (from 1.9 to 2.5); however, the mean cross-clamp time did not change. The surgical mortality rate for the entire study was 3.4%. In group 1, the mortality was 7.5% but decreased rapidly and remained steady throughout the rest of the study. The use of the Freestyle stentless conduit in a single practice over time shows a distinct learning curve. With experience, valves are placed in younger, sicker patients who require more complex surgery. Surgical outcomes and efficiency improve with acquired surgical expertise.
Stentless aortic bioprosthesis performance may be affected by geometric distortion, and intraoperative echocardiography typically is used to assess prosthetic valve function. The impact of minimal or mild post-pump aortic regurgitation has not been previously investigated. Intraoperative post-pump transesophageal echocardiograms and follow-up transthoracic echocardiograms (up to 3 years' postoperatively) were reviewed for 96 patients who underwent implantation of Freestyle (Medtronic) stentless aortic bioprostheses. Minimal or mild aortic regurgitation was present post-pump in 50 of 96 (52%) patients. On early follow-up examination (n = 80), no patient had more than mild aortic regurgitation. Aortic regurgitation had completely resolved in 24 of 39 (62%) patients with post-pump aortic regurgitation, including 15 of 19 (79%) patients with minimal paravalvular regurgitation. The incidence of mild aortic regurgitation at 2 and 3 years did not appear different between patients with and those without post-pump aortic regurgitation. Minimal or mild aortic regurgitation is common on intraoperative post-pump transesophageal echocardiography immediately after implantation of stentless aortic bioprostheses. Resolution is common, especially of small paravalvular jets. Minimal or mild post-pump aortic regurgitation infrequently results in even mild aortic regurgitation on early follow-up evaluation and does not appear to predict clinically significant progression of aortic regurgitation on long-term follow-up evaluation.
Stentless tissue valves may provide more favorable hemodynamics than conventional stented valves. Hemodynamic findings from a large multicenter trial have not been previously reported. The present report describes the hemodynamic findings from a multinational, multicenter study after implantation of the Toronto SPV valve. A total of 577 patients underwent aortic valve replacement with the Toronto SPV valve at 12 sites in 3 countries. Echocardiograms were recorded in the early postoperative period, 3 to 6 months after surgery, 1 year after surgery, and yearly thereafter, with follow-up to 3 years. Gradients decreased and effective orifice area increased in the months after surgery. One year after surgery, mean gradient for valve sizes 20 to 22, 23, 25, 27, and 29 mm was 7.3 +/- 4.4, 7.4 +/- 4.5, 6.1 +/- 3.3, 4.9 +/- 2.4, and 4.0 +/- 2.1 mm Hg, respectively; effective orifice area was 1.3 +/- 0.7, 1.5 +/- 0.5, 1.7 +/- 0.4, 2.0 +/- 0.4, and 2.4 +/- 0.6 cm2, respectively. There was a very low prevalence of significant aortic regurgitation at all time periods. There was significant left ventricular (LV) mass regression between the early and 3- to 6-month periods and between the 3- to 6-month and 1-year postoperative periods. The Toronto SPV valve has an excellent hemodynamic profile supported by significant regression of LV hypertrophy in the year after implantation. Data through 3 years demonstrates maintenance of low gradients and freedom from significant aortic regurgitation.
Arbutamine stress echocardiography was performed in 81 patients with suspected coronary artery disease. Arbutamine infusion, using a dedicated closed-loop delivery device, provided comparable myocardial stress in patients receiving beta-1 blockers versus those who were not.
Closed-loop arbutamine stress echocardiography has been shown to be safe and effective for detecting coronary artery disease (CAD) using a standardized infusion protocol and centralized core laboratory analyses. However, the accuracy of arbutamine stress echocardiography using local test interpretation has not been previously tested in a large population. The present study reports the safety, sensitivity, and specificity of arbutamine stress echocardiography in a multicenter trial allowing user-defined, nonstandardized protocols and local test interpretation. In all, 1,070 patients underwent arbutamine stress testing at 81 sites. Heart rate increased from 73 +/- 13 to 124 +/- 15 beats/min, systolic blood pressure from 144 +/- 24 to 174 +/- 25 mm Hg, and pressure rate product x 10(3) from 10.5 +/- 2.8 to 19.6 +/- 3.9. Among 1,070 patients, there were only 2 (0.2%) significant adverse events related to arbutamine, both of which resolved completely with appropriate therapy. There were no incidents of ventricular fibrillation, sustained ventricular tachycardia, or death related to testing. Among 242 patients who underwent arbutamine stress echocardiography and diagnostic coronary angiography within 12 weeks, sensitivity and specificity for detection of CAD were 71% (95% confidence interval 64% to 77%) and 67% (95% confidence interval 52% to 80%), respectively. Closed-loop arbutamine stress echocardiography is a safe and effective method for evaluating CAD in clinical practice.
OBJECTIVES: The objective of this study was to define the range of clinical presentations, echocardiographic findings, and underlying final diagnoses in patients with clinically suspected acute aortic dissection. METHODS AND RESULTS: This study was designed as a retrospective review of clinical and echocardiographic data in consecutive patients evaluated for clinically suspected acute aortic dissection. The study population consisted of 75 studies in 74 consecutive patients referred for urgent or emergency evaluation because of signs and symptoms suggesting acute aortic dissection. A history and physical examination designed to elicit the cause of chest pain, evidence of congestive heart failure, and other cardiovascular abnormalities was performed in each patient. All patients underwent transesophageal echocardiography by experienced operators. Routine 12-lead electrocardiograms and chest radiographs were available for review in the majority of patients. Magnetic resonance imaging or computed tomography was performed in only 5 (6%) and 34 (44%) patients, respectively. Contrast aortography was performed in 21 (27%) patients. For the entire patient cohort, the most prevalent symptom was chest pain alone (n = 31; 41%) or chest pain in conjunction with back pain (n = 23; 31%). Classic "tearing" pain was an infrequent symptom. Syncope or other neurologic findings were present in 15 (20%) patients. Acute aortic dissection was responsible for 34 (45%) of the 75 presentations, with 31 (41% of total evaluations, 92% of dissections) involving the ascending aorta (Stanford type A, DeBakey type 1 or 2). Alternate major cardiovascular diagnoses, including acute myocardial infarction, primary valvular disease, or pericardial disease, were established in 12 (16%) cases. Aortic pathology, other than dissection, was found in 15 (20%) cases. Transesophageal echocardiography established the diagnosis responsible for the symptoms in 61 (81%) cases. CONCLUSIONS: Symptoms in patients with acute aortic dissection are more variable than commonly recognized. Transesophageal echocardiography is an accurate primary diagnostic tool in patients with clinically suspected acute aortic dissection. It allows rapid diagnosis of dissection and can identify alternate cardiovascular pathology responsible for the symptoms in a significant number of patients without acute dissection.