David S. Bach

Intermediate-Term Outcome Of Mitral Reconstruction In Cardiomyopathy

OBJECTIVE Severe mitral regurgitation is a frequent complication of end-stage cardiomyopathy that contributes to heart failure and predicts a poor survival. We studied the intermediate-term outcome of mitral reconstruction in 48 patients who had cardiomyopathy with severe mitral regurgitation and were operated on between June 1993 and June 1997. METHODS Ages ranged from 33 to 79 years (63 +/- 6 years) with left ventricular ejection fractions of 8% to 25% (16% +/- 3%). All patients were receiving maximal drug therapy and were in New York Heart Association class III-IV with severe, refractory 4+ mitral regurgitation. Operatively, all 48 had undersized flexible annuloplasty rings inserted, 7 had coronary bypass grafts for incidental disease, 11 had prior bypass grafts, and 11 also had tricuspid valve repair. RESULTS One operative death occurred as a result of right ventricular failure. Postoperative transesophageal echocardiography revealed mild mitral regurgitation in 7 patients and no mitral regurgitation in 41. There were 10 late deaths, 2 to 47 months after mitral reconstruction. The 1- and 2-year actuarial survivals have been 82% and 71%. At a mean follow-up of 22 months, the number of hospitalizations for heart failure has decreased, and 1 patient has had heart transplantation. Significantly, New York Heart Association class improved from 3.9 +/- 0.3 before the operation to 2.0 +/- 0.6 after the operation. Twenty-four months after the operation, left ventricular volume and sphericity have decreased, whereas ejection fraction and cardiac output have increased. CONCLUSION Whether this favorable modification of left ventricular function and geometry will persist remains unknown. However, mitral repair for cardiomyopathy with mitral regurgitation allows new strategies for these patients.

Early outcome of mitral valve reconstruction in patients with end-stage cardiomyopathy

Uncontrollable severe mitral regurgitation is a frequent complication of end-stage cardiomyopathy, significantly contributing to heart failure in these patients, and predicts a poor survival. Although elimination of mitral valve regurgitation could be most beneficial in this group, corrective mitral valve surgery has not been routinely undertaken in these very ill patients because of the presumed prohibitive operative mortality. We studied the early outcome of mitral valve reconstruction in 16 consecutive patients with cardiomyopathy and severe, refractory mitral regurgitation operated on between June 1993 and April 1994. There were 11 men and five women, aged 44 to 78 years (64 +/- 8 years) with left ventricular ejection fractions of 9% to 25% (16% +/- 5%). Preoperatively all patients were in New York Heart Association class IV, had severe mitral regurgitation (graded 0 to 4+ according to color flow Doppler transesophageal echocardiography) and two were listed for transplantation. Operatively, a flexible annuloplasty ring was implanted in all patients. Four patients also had single coronary bypass grafting for incidental coronary disease. In four patients the operation was performed through a right thoracotomy because of prior coronary bypass grafting, and four patients also underwent tricuspid valve reconstruction for severe tricuspid regurgitation. No patient required support with an intraaortic balloon pump. There were no operative or hospital deaths and mean hospital stay was 10 days. There were three late deaths at 2, 6, and 7 months after mitral valve reconstruction, and the 1-year actuarial survival has been 75%. At a mean follow-up of 8 months, all remaining patients are in New York Heart Association class I or II, with a mean postoperative ejection fraction of 25% +/- 10%. There have been no hospitalizations for congestive heart failure, and a decrease in medications required has been noted. For patients with cardiomyopathy and severe mitral regurgitation, mitral valve reconstruction as opposed to replacement can be accomplished with low operative and early mortality. Although longer term follow-up is mandatory, mitral valve reconstruction may allow new strategies for patients with end-stage cardiomyopathy and severe mitral regurgitation, yielding improvement in symptomatic status and survival.

Range of tricuspid regurgitation velocity at rest and during exercise in normal adult men: implications for the diagnosis of pulmonary hypertension☆

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.

Evaluation of Patients With Severe Symptomatic Aortic Stenosis Who Do Not Undergo Aortic Valve Replacement: The Potential Role of Subjectively Overestimated Operative Risk

Background—Some patients with severe symptomatic aortic stenosis (AS) do not undergo aortic valve replacement (AVR) despite demonstrated symptomatic and survival advantages and despite unequivocal guideline recommendations for surgical evaluation. Methods and Results—In 3 large tertiary care institutions (university, Veterans Affairs, and private practice) in Washtenaw County, Mich, patients were identified with unrefuted echocardiography/Doppler evidence of severe AS during calendar year 2005. Medical records were retrospectively reviewed for symptoms, referral for AVR, calculated operative risk for AVR, and rationale as to why patients did not undergo valve replacement. Of 369 patients with severe AS, 191 (52%) did not undergo AVR. Of these, 126 (66%, 34% of total) had symptoms consistent with AS. The most common reasons cited for absent intervention were comorbidities with high operative risk (61 patients [48%]), patent refusal (24 patients [19%]), and symptoms unrelated to AS (24 patients [19%]). Operated patients had a lower Society of Thoracic Surgery-calculated perioperative mortality risk than unoperated patients (1.8% [interquartile range, 1.0 to 3.0%] versus 2.7% [interquartile range, 1.6 to 5.5%], P<0.001). However, 28 (24%) of 126 unoperated symptomatic patients had a calculated perioperative risk less than the median risk for patients who underwent AVR. Only 57 (30%) of 191 unoperated patients were evaluated by a cardiac surgeon. There were similar rates of intervention across practice settings, and similar rates of unoperated patients despite symptoms and low operative risk. Conclusions—One third of patients with severe AS are symptomatic but do not undergo AVR, with similar findings in multiple practice environments. For most unoperated patients, objectively calculated operative risks did not appear prohibitive. Despite this, a minority of unoperated patients were referred for surgical consultation. Some patients with severe symptomatic AS may be inappropriately denied access to potentially life-saving therapy.

Two-dimensional and dobutamine stress echocardiography in the preoperative assessment of patients with end-stage liver disease prior to orthotopic liver transplantation.

Orthotopic liver transplantation is an established therapy for end-stage liver disease. This study evaluated the range of cardiovascular abnormalities in patients undergoing evaluation for orthotopic liver transplantation and determined the prognostic implications of abnormal echocardiographic features, including ischemia during dobutamine stress echocardiography, in predicting postoperative cardiac events. Two-dimensional echocardiography was performed in 190 patients for assessment of left ventricular function, valvular pathology, and pulmonary hypertension. Dobutamine stress echocardiography was performed in 165 patients for evaluation of inducible ischemia. Contrast echocardiography for detection of intrapulmonary shunting was performed in 125 patients at rest and in 99 during dobutamine stress. Left ventricular dysfunction, significant valvular regurgitation, and inducible ischemia were identified in <1O% of patients. Pulmonary hypertension, left ventricular hypertrophy and > or = moderate intrapulmonary shunting were present in 12%, 16%, and 26% of patients, respectively. Severe intrapulmonary shunting predicted death prior to transplantation (P=0.01). Of the 71 transplanted patients, major perioperative events included global left ventricular dysfunction in four patients and myocardial infarction in one patient with normal coronary arteries. No preoperative echocardiographic parameters, including ischemia on dobutamine echocardiography, predicted these perioperative events. No cardiac events related to obstructive coronary artery disease occurred in the 154 patients without ischemia on dobutamine stress echocardiography. The majority of patients with end-stage liver disease, including those with alcoholic cirrhosis, have normal cardiac function on two-dimensional echocardiography. Severe intrapulmonary shunting portends a poor prognosis in patients awaiting transplantation. A negative dobutamine stress echocardiogram appears useful in excluding patients at risk for perioperative cardiac events related to obstructive coronary artery disease.

Quantitative Doppler tissue imaging of the left ventricular myocardium: Validation in normal subjects

Doppler tissue imaging (DTI) is a new echocardiographic imaging technique from which quantitative data regarding myocardial velocity can be extracted. The purpose of this study was to compare endocardial velocities determined from DTI with those determined from M-mode echocardiography and to assess the range of myocardial velocities in normal subjects. Nineteen subjects were evaluated by M-mode echocardiography and quantitative DTI for maximal systolic velocities of the anteroseptal and inferoposterior walls. Mid-myocardial and epicardial velocities were also measured by DTI for each wall. Maximal systolic velocities of the anteroseptal and inferoposterior endocardium determined by DTI correlated significantly with those derived from M-mode echocardiography (r = 0.87). The velocity of the inferoposterior wall by DTI (27.3 +/- 4.8 mm/sec) was greater than that of the anteroseptum (20.8 +/- 4.1 mm/sec) by a mean difference of 7.0 +/- 5.7 mm/sec (p < 0.001). A peak velocity gradient of 5.9 +/- 3.5 mm/sec (p < 0.001) between the epicardium to endocardium was detected. These data confirm that (1) regional myocardial velocities may be quantified with DTI in human beings; (2) the high resolution of DTI allows velocities to be determined at different levels within the myocardium; and (3) heterogeneity of myocardial velocities may be demonstrated in normal subjects.

Early improvement in congestive heart failure after correction of secondary mitral regurgitation in end-stage cardiomyopathy

Mitral regurgitation frequently complicates dilated cardiomyopathy, aggravates volume overload of the left ventricle, and contributes to symptoms of congestive heart failure. This study was performed to assess the impact of mitral valve reconstruction in nine consecutive patients with severe mitral regurgitation resulting from end-stage dilated cardiomyopathy. Clinical and echocardiographic follow-up were obtained 17 +/- 5 and 16 +/- 6 weeks after surgery, respectively. There were no operative or early deaths. All patients noted symptomatic improvement postoperatively, and there was a decrease of at least one New York Heart Association functional class (3.9 +/- 0.3 to 1.7 +/- 0.5, p < 0.001). Quantitative echocardiography/Doppler demonstrated a small but significant decrease in left ventricular end-diastolic volume (317 +/- 111 ml to 291 +/- 105 ml, p = 0.04) and increases in ejection fraction (18 +/- 5% to 24 +/- 9%, p = 0.02) and forward cardiac output (3.1 +/- 1.0 to 4.6 +/- 0.8 L/min, p < 0.01) on follow-up. Mitral valve reconstruction for the correction of mitral regurgitation in patients with end-stage dilated cardiomyopathy results in improved symptomatic status on early follow-up accompanied by evidence of improvement in left ventricular performance.

Improvement Following Correction of Secondary Mitral Regurgitation in End-Stage Cardiomyopathy With Mitral Annuloplasty

Twenty consecutive patients with severe mitral regurgitation secondary to end-stage dilated cardiomyopathy underwent mitral annuloplasty for refractory symptoms of heart failure. On follow-up 18 +/- 4 months after annuloplasty, 14 patients (70%) were alive, all 14 noted symptomatic improvement, and quantitative echocardiographic/Doppler demonstrated decreases in left ventricular volume and sphericity accompanied by increases in ejection fraction and forward cardiac output.

Effect of Ventricular Shock Strength on Cardiac Hemodynamics

Ventricular Defibrillation and Cardiac Function. Introduction: The effect of implantable defibrillator shocks on cardiac hemodynamics is poorly understood. The purpose of this study was to test the hypothesis that ventricular defibrillator shocks adversely effect cardiac hemodynamics.

Quantitative Doppler tissue imaging for assessment of regional myocardial velocities during transient ischemia and reperfusion

Doppler tissue imaging (DTI) is a new noninvasive imaging modality that directly interrogates myocardial velocity with high temporal and spatial resolution. This study was designed to test the hypothesis that quantitative DTI provides unique information regarding regional myocardial systolic and diastolic function during acute ischemic events. Myocardial velocities were quantified during the acute ischemic and reperfusion phases of 13 elective percutaneous coronary angioplasty procedures in 12 patients. In myocardium subtended by angioplasty vessels, peak velocities decreased during occlusive balloon inflation (from 21.2 +/- 9.8 to -0.6 +/- 4.0 mm/sec in systole [p < 0.001] and from 21.7 +/- 9.2 to -0.6 +/- 3.9 mm/sec in diastole [p < 0.001]). During early reperfusion, velocities exceeded those observed at baseline (p = 0.003). In regions remote from the treated artery, peak myocardial velocities increased in the absence of significant stenosis but remained unchanged or decreased in the presence of significant stenosis of the associated vessel. We conclude that (1) myocardial velocities rapidly decrease during acute ischemia and show a rebound increase after reperfusion, and (2) in regions remote from ischemia, velocities display distinct patterns on the basis of the presence or absence of obstructive coronary disease in the associated vessel. Quantitative DTI is a useful tool for the assessment of myocardial velocity and may provide new insights into myocardial systolic and diastolic function.