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Biomedical subjects

T E David

Publications and source records attributed to T E David.

At least 127 records · Page 7Linked to original sources
PubMed1989

Mitral valve annuloplasty: the effect of the type on left ventricular function.

This study was undertaken to determine whether rigid-ring annuloplasty and flexible-ring annuloplasty have the same effect on left ventricular function in patients with chronic mitral regurgitation secondary to degenerative disease of the mitral valve. Twenty-five patients who underwent isolated mitral valve repair and required annuloplasty were randomized into two groups: rigid-ring and flexible-ring annuloplasty. Left ventricular function was assessed by echocardiography and radionuclide angiography on the day before operation and 2 to 3 months later. Preoperative left ventricular function was similar in the two groups of patients. Postoperatively, left ventricular end-diastolic diameter and volume decreased significantly in both groups. The left ventricular end-systolic diameter and volume decreased significantly only in patients with a flexible annuloplasty ring. Left ventricular systolic function as assessed by pressure-volume relationships was significantly better in patients with a flexible ring (p less than 0.02 by analysis of covariance), and left ventricular performance measured by stroke volume-end-diastolic volume relationships was also better in these patients (p less than 0.05 by analysis of covariance). These data indicate that patients with a flexible annuloplasty ring have better left ventricular systolic function than patients with a rigid annuloplasty ring 2 to 3 months after mitral valve reconstruction for chronic mitral regurgitation secondary to degenerative disease of the mitral valve.

Adult↗
PubMed1989

Intravenous labetalol versus sodium nitroprusside for treatment of hypertension postcoronary bypass surgery.

Hypertension is common following coronary artery bypass surgery. The safety of labetalol, a recently released combined alpha-1 and beta-adrenergic blocking agent for treatment of hypertension in this clinical situation is controversial. The authors compared the hemodynamic effects of labetalol with those of sodium nitroprusside (SNP) in 91 patients with good left ventricular function and equally severe coronary artery disease and in whom coronary artery bypass surgery had been just completed. They were anesthetized using fentanyl, diazepam, and enflurane. If hypertension developed postoperatively, patients were randomized to receive labetalol, 2 mg/min to a maximum of 300 mg (20 patients) or sodium nitroprusside in 0.5 micrograms.kg-1.min-1 increments by infusion (20 patients) to return blood pressure to normal. Compared with control values, labetalol brought about significant (P less than 0.05) reductions in heart rate, and cardiac index. No change was noted in stroke volume or systemic vascular resistance, but slight increases were found in central venous pressure and pulmonary capillary wedge pressure. Sodium nitroprusside treatment caused significant increases in heart rate and cardiac index while reducing diastolic blood pressure, central venous pressure, and pulmonary capillary wedge pressure. Stroke volume remained unchanged. Following the study period, blood pressure was controlled in all patients with SNP. Total doses of SNP in the 16 h following the study period were significantly less in the labetalol group (46.6 +/- 11.7 mg) versus (116.1 +/- 10.3 mg) in the SNP group (P less than 0.05). In this clinical circumstance, labetalol can be safe and effective for controlling hypertension, but its mechanism of achieving this effect varies from that for sodium nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Replacement of chordae tendineae with expanded polytetrafluoroethylene sutures.

One or more primary chordae tendineae of the anterior leaflet of the mitral valve was replaced with expanded polytetrafluoroethylene (PTFE) sutures in 22 patients as part of mitral valve reconstructive procedure. One patient with flail anterior leaflet of the tricuspid valve also had replacement of chordae tendineae with a PTFE suture. These patients have been followed from 2 to 48 months, mean of 17 months. Valve function has been assessed annually by Doppler echocardiography. The PTFE chordae cannot be visualized by two- dimensional echocardiography but they seem to allow the leaflet to move normally during the cardiac cycle. The function of the repaired valve in these 23 patients has remained most satisfactory during the observed interval. We believe that PTFE sutures can be used safely to replace diseased chordae tendineae of the mitral and tricuspid valves when conventional techniques of chordal repair are not possible.

Chordae Tendineae↗
PubMed1989

Surgical treatment of aortic root abscess.

A significant number of patients with infective aortic valve endocarditis develop aortic annular abscess. Although antibiotics may occasionally sterilize an aortic root abscess, most patients require surgical intervention. A review of our experience with 21 consecutive patients surgically treated for aortic root abscess disclosed that 13 patients had prosthetic valve and eight had native aortic valve endocarditis. The predominant microorganism was Staphylococcus aureus, particularly in those patients with native aortic valve endocarditis. The abscess was limited to the aortic annulus in 10 patients and was either multiple or had perforated the left ventricular outflow tract in 11 patients. Most patients were desperately ill at the time of operation. Repair was accomplished by aggressive debridement of all apparently infected tissue and reconstruction of the left ventricular outflow tract with autologous pericardium. Although postoperative complications were common, only one patient died in hospital. Operative survivors have been followed up from 3 to 68 months (mean, 29 months). One patient died of complications of repair of a thoracoabdominal aneurysm 34 months after surgery; his prosthetic aortic valve and patch were intact at autopsy. No patient has experienced recurrent infection, pericardial patch aneurysm, or prosthetic valve dehiscence.

Abscess↗
PubMed1989

The changing pattern of coronary artery bypass surgery.

Recent advances in interventional cardiology have altered the profile of patients referred for coronary artery bypass surgery. In recent years, the proportion of high-risk patients has increased dramatically. To evaluate the impact of the changing pattern of surgical patients, we prospectively followed up 7,334 patients who had coronary artery bypass surgery between 1982 and 1986. Multivariate analysis identified the following risk factors for operative mortality: urgency of surgery, left ventricular ejection fraction, age, female sex, previous bypass surgery, and left main coronary artery stenosis. Perioperative mortality has remained stable despite an increasing incidence of high-risk patients. However, perioperative morbidity has increased, due to the large number of high-risk patients. A multivariate analysis was performed by year to identify temporal trends in risk factors. Urgency of surgery, age, and previous bypass surgery have become more significant predictors of mortality with respect to time, whereas female sex, left ventricular ejection fraction, and left main coronary artery stenosis have become less significant determinants of mortality. Our results demonstrate the critical dependence of mortality and morbidity rates on the case mix, and further improvements in the results of coronary artery bypass surgery will require better strategies for the increasing number of high-risk patients.

Age Factors↗
PubMed1989

Valvular surgery in the elderly.

In previous studies from this university, advanced age was identified as an independent predictor of operative mortality for valvular surgery. Therefore, between January 1982 and December 1986, early results were compared in 469 patients greater than 70 years old (Old; 74.0 +/- 3.4 years, mean +/- SD) and in 2,040 patients less than 70 years old (Young; 53.7 +/- 12.1 years). Patients underwent single- or multiple-valve repair or replacement with or without concomitant coronary artery bypass surgery. Data consisting of 31 clinical and angiographic variables were collected prospectively and were analyzed by univariate and multivariate statistics. Old patients were characterized by having more frequent left ventricular dysfunction (left ventricular ejection fraction less than 40%: Old, 33.5%; Young, 22.4%; p less than 0.001), coronary artery disease (Old, 54.5%; Young, 24.2%; p less than 0.001), and urgent surgery (Old, 15.6%; Young, 11.8%; p = 0.02). Aortic valve procedures (Old, 59.7%; Young, 40.1%; p less than 0.001) and concomitant coronary artery bypass surgery (Old, 46.4%; Young, 20.3%; p less than 0.001) were performed more commonly in the Old patient. Operative mortality occurred in 10.0% of Old patients compared with 5.6% of Young patients (p less than 0.001), and major morbidity (low-output syndrome, perioperative myocardial infarction, intra-aortic balloon pump counterpulsation, and stroke) occurred significantly more frequently (p less than 0.001) in the Old. Stepwise logistic regression identified that urgent operation (p = 0.002), mitral or double-valve surgery (p = 0.004), coronary artery disease especially when not treated by bypass surgery (p = 0.02), female gender (p = 0.02), and left ventricular dysfunction (p = 0.05) independently predicted operative death in the Old population. The significant predictors of mortality in the Young patient were urgent operation (p less than 0.001), New York Heart Association class IV (p less than 0.001), associated tricuspid valve disease (p = 0.002), decreased left ventricular function (p = 0.01), valvular re-replacement (p = 0.02), and increasing age (p = 0.03). The predicted probability of operative mortality in Old patients ranged between 0.9 +/- 0.5% and 76 +/- 16%. Elderly patients in good risk categories should be offered surgical intervention for correction of valvular lesions. Alternative therapy may be indicated in patients with multiple risk factors.

Age Factors↗
PubMed1988

Calcium channel blockade does not offer adequate protection from perioperative myocardial ischemia.

This study aimed to detect the difference in hemodynamic and electrocardiographic responses during the prebypass period in patients undergoing coronary bypass grafting who were receiving beta-adrenergic blocking drugs, calcium entry blocking drugs, or both beta-adrenergic and calcium entry blocking drugs. Electrocardiographic evidence of myocardial ischemia was noted significantly more frequently in patients receiving calcium entry blocking drugs alone at induction of anesthesia (P less than 0.03), skin incision (P less than 0.05), and sternotomy (P less than 0.002). Heart rate at sternotomy was significantly higher in patients receiving calcium entry blocking drugs (P less than 0.02) as compared to patients receiving beta-adrenergic blocking drugs or the combination of both drugs. In conclusion, patients treated with calcium entry blocking drugs alone had significantly higher incidence of perioperative ischemic ECG changes compared with patients receiving beta-adrenergic blocking drugs alone or in combination with calcium channel blocking drugs.

Adrenergic beta-Antagonists↗
PubMed1988

Aortic valve replacement with stentless porcine bioprostheses.

Aortic valve replacement with stentless porcine valve should provide superior hemodynamic results to stented porcine valve because the obstruction caused by the stent and the sewing ring is eliminated. In addition, the coronary sinuses of the recipient may allow for better dissipation of the mechanical stress to which the leaflets are subjected during diastole, thus enhancing durability of the heterograft. Aortic valve replacement with stentless glutaraldehyde-fixed aortic porcine bioprosthesis was carried out successfully in six young sheep. These animals were hemodynamically evaluated at 3 to 6 months after operation and found to have no resting gradients or any degree of aortic regurgitation. Explantation of the aortic heterograft revealed that it was well healed in the aortic root and had no evidence of any calcification. A clinical trial has been initiated and the results in the first five humans who underwent aortic valve replacement with a stentless porcine aortic bioprosthesis have been satisfactory.

Aged↗
PubMed1988

Reconstructive procedures in heart valve disease.

The percentage of patients who undergo valve repair has increased considerably during the past decade. Valve repair is particularly important in patients with atrioventricular valve disease since it provides better results than replacement. Aortic valve repair is presently performed only in selected patients with aortic stenosis and insufficiency. There is a renewed interest in aortic valve debridement in patients with calcific aortic stenosis. Mitral valve repair can be performed in most patients with mitral insufficiency and in many with mitral stenosis. The surgical techniques for mitral valve repair are well established and are reproducible. The tricuspid valve is almost always reparable in patients with tricuspid disease associated with mitral valve disease.

Aortic Valve↗
PubMed1988

Predictors of operative survival after valve replacement.

To identify the independent predictors of operative mortality, we examined 31 preoperative clinical and hemodynamic variables in 2,488 patients undergoing valvular surgery between 1982 and 1986. The operative mortality was 5.3% in 1,098 patients after aortic valve surgery, 6.6% in 1,107 after mitral valve surgery, and 10.1% in 283 after double valve surgery. Multivariate statistical analysis demonstrated that urgent surgery, endocarditis requiring urgent surgery, previous aortic valve surgery, coronary artery disease, and age were independent risk factors for aortic valve surgery. Urgent surgery, endocarditis, age, coronary artery disease, and preoperative ventricular ejection fraction were independent predictors of mortality after mitral valve surgery. The predictors of mortality after double valve surgery were urgent surgery, age, preoperative ventricular ejection fraction, and tricuspid valve disease. Gender and the type of valvular lesion, procedure, and prosthesis did not independently influence operative mortality. Strategies to diminish operative mortality should include careful assessment of the risks and benefits in elderly patients, early operative intervention before deterioration that necessitates urgent surgery, and use of improved techniques of myocardial protection in high-risk subgroups.

Adult↗
PubMed1987

Reconstruction of the mitral anulus.

The mitral anulus was reconstructed with autologous pericardium in nine patients. Six patients had infective endocarditis with one or more abscesses in the anulus, and three had an iatrogenically damaged anulus. In patients with disruption of the mitral anulus limited to its posterior portion, a semicircular patch of pericardium was sutured directly to the endocardium of the left ventricle. In patients with multiple defects in the anulus, circumferential reconstruction of the mitral ring with pericardium was performed. In cases in which abscesses involved the central fibrous body, pericardium was used to reconstruct both the mitral anulus and the aortic root. Eight patients survived and have remained well for a mean of 8 months. There has been no prosthetic or patch dehiscence. All patients experienced substantial functional improvement. This experience indicates that the disrupted mitral anulus can be successfully reconstructed with autologous pericardium that is sutured directly to the endocardium of the left ventricle.

Adult↗
PubMed1987

Reconstruction of the left ventricle with autologous pericardium.

Autologous pericardium was used to reconstruct different parts of the left ventricle in 25 desperately ill patients. Fourteen patients had intractable sepsis resulting from infective endocarditis and myocardial abscess and 10 patients had noninfectious disorders. Of the patients with infections, 12 had valvular endocarditis with periannular abscess and three had interventricular septal abscess. The noninfected patients had acute rupture of the ventricular wall after mitral valve replacement (one patient) heavily calcified or surgically absent mitral anulus (three patients), or rupture of the interventricular septum after acute myocardial infarction (six patients). The interventricular septum, the posterior wall of the left ventricle, and the periannular areas were reconstructed by suturing appropriately tailored pericardial patches directly to the endocardium. In patients who also required valve replacement, the prosthetic valve was partially or completely secured to the pericardial patch. There were three operative deaths. All three patients were in either septic or cardiogenic shock before operation and in none of them was the death related to the pericardial patch. All 22 survivors have been observed from 3 to 34 months, an average of 14 months. There has been no case of patch dehiscence, patch aneurysm, prosthetic valve dehiscence, or recurrent endocarditis. Autologous pericardium appears to be safe for reconstruction of the left ventricle. It is easy to handle and problems with suture line bleeding are practically nonexistent.

Endocarditis, Bacterial↗
PubMed1986

A physiological approach to surgery for acute rupture of the papillary muscle.

There is controversy regarding the optimal management of patients in whom acute papillary muscle rupture develops. This study evaluates the effect of division of the anterolateral papillary muscle on left ventricular (LV) function and compares two methods of treatment--mitral valve replacement (MVR) and mitral valve repair. Thirteen pigs were placed on cardiopulmonary bypass, and interventions were performed in an isolated beating heart preparation. LV function was assessed with a compliant intraventricular balloon at baseline, after division of the anterolateral papillary muscle (Divided), after repair of the divided papillary muscle (Repair), and finally after MVR. Division of the anterolateral papillary muscle caused a significant deterioration in LV function. Function was maintained at this level after mitral valve repair but deteriorated with MVR. Developed pressure measured at baseline was 179 +/- 13 mm Hg; Divided, 148 +/- 11 mm Hg (p less than 0.05 versus baseline); Repair, 149 +/- 15 mm Hg; and MVR, 95 +/- 8 mm Hg (p less than 0.05 versus Divided) at a balloon volume of 20 ml. These results suggest that LV function is impaired by papillary muscle rupture. Repair of the ruptured papillary muscle is associated with better LV function than is MVR.

Acute Disease↗