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Biomedical subjects

T E David

Publications and source records attributed to T E David.

At least 19 recordsLinked to original sources
PubMed1995

The Hancock II bioprosthesis at ten years.

The Hancock II bioprosthesis was used for heart valve replacement in 843 patients from 1982 to 1993. Aortic valve replacement (AVR) was performed in 536 patients, mitral valve replacement (MVR) in 250, and aortic and mitral valve replacement (DVR) in 57. The mean age was 64 +/- 12 years. Before operation, 80% of the patients were in New York Heart Association functional class III or IV; approximately one-third of the patients had coronary artery disease, and 60 patients had ascending aorta aneurysm. There were 47 operative deaths (AVR, 4%; MVR, 7%; DVR, 10%) and 147 late deaths. Follow-up was complete in 98.6% of the patients and extended from 3 to 140 months (mean, 59 months). At the last follow-up, 84% of the patients were in New York Heart Association class I or II. The actuarial survival at 10 years was 63% +/- 4% for AVR, 55% +/- 5% for MVR, and 53% +/- 9% for DVR. At the end of 10 years, the freedom from thromboembolic complications was 80% +/- 4% for AVR, 88% +/- 3% for MVR, and 86% +/- 5% for DVR; the freedom from endocarditis was 95% +/- 2% for AVR, 96% +/- 1% for MVR, and 87% +/- 5% for DVR; the freedom from primary tissue failure was 92% +/- 3% for AVR, 81% +/- 6% for MVR, and 65% +/- 16% for DVR; and the freedom from reoperation was 89% +/- 2% for AVR, 81% +/- 6% for MVR, and 61% +/- 15% for DVR. The durability of this bioprosthetic valve was affected by the patient's age and by the position where it was implanted. The clinical results of the Hancock II bioprosthesis at 10 years are comparable to those of other current porcine and pericardial valves.

Actuarial Analysis↗
PubMed1995

Postinfarction ventricular septal rupture: repair by endocardial patch with infarct exclusion.

A novel operative technique for postinfarction ventricular septal defect has been used in 44 consecutive patients. The operation consists of excluding rather than excising the infarcted septum and ventricular walls. This is accomplished by performance of a left ventriculotomy through the infarcted muscle and securing a glutaraldehyde-fixed bovine pericardium patch to the endocardium of the left ventricle all around the infarcted myocardium. The ventriculotomy is simply closed over the pericardial patch. There were 21 men and 23 women whose mean age was 69 +/- 7 years. Twenty-nine patients were in cardiogenic shock at the time of operation. All patients had Doppler echocardiography and coronary angiography before operation. All but two patients were operated on during the acute phase of the myocardial infarction. There were six operative deaths. Postoperative complications included renal failure in 10 patients and respiratory failure in 18. Severe right ventricular dysfunction was the only independent predictor of operative mortality. Patients have been followed up for a mean of 40 +/- 34 months. There have been six late deaths and three of these were because of cardiac problems. The actuarial survival at 6 years was 66% +/- 7%. Only one patient had a small residual ventricular septal defect. Late postoperative assessment of ventricular function by echocardiography revealed that most patients had normal or mild impairment of right ventricular function and mild or moderate impairment of left ventricular function. Repair of acute postinfarction ventricular septal defect by endocardial patch with infarct exclusion of the left ventricule probably avoids additional damage to the right ventricle, remodels the acutely infarcted left ventricle, and enhances survival.

Aged↗
PubMed1995

Reconstruction of the mitral anulus. A ten-year experience.

Reconstruction of the mitral anulus was done in 93 patients because of extensive calcification in 24, infective endocarditis with annular abscess in 27, damaged anulus as a result of previous valve replacement in 36, and rupture of the posterior wall of the left ventricle after mitral valve replacement in 6. The reconstruction was done with fresh autologous pericardium in 30 patients, glutaraldehyde-fixed bovine pericardium in 56, and Dacron graft in 7. An appropriately tailored patch was sutured to the endocardium of the left ventricle or to fibrous skeleton of the heart, or to both. Sixty patients had had previous operation; most patients were in New York Heart Association functional class IV and 15 were in shock. The mitral valve was repaired in 10 patients and replaced in 83. Other procedures were aortic valve replacement in 40, tricuspid valve repair in 25, coronary artery bypass in 12, and replacement of the ascending aorta in 2. Eight patients died in the perioperative period. Postoperative complications were common. Patients were followed up from 12 to 96 months, with a mean of 30 months. There have been 18 late deaths, mostly cardiac. The actuarial survival at 5 years was 68% +/- 6%. A total of 8 patients have required reoperation: 4 because of endocarditis, 2 because of bioprosthetic valve failure, and 2 because of patch dehiscence. The freedom from reoperation was 80% +/- 8% at 5 years. The freedom from patch dehiscence was 95% +/- 4% at 5 years. Reconstruction of the mitral anulus has been an extremely useful operative technique for patients with complex mitral valve disease.

Adolescent↗
PubMed1995

Is body size the cause for poor outcomes of coronary artery bypass operations in women?

Although small body size and coronary artery diameter are recognized as major contributors to the increased risk of coronary artery bypass grafting in women, few studies have established the independent influence of body size and gender on outcome. We studied 7025 consecutive patients (5694 men, 1331 women) undergoing isolated coronary artery bypass grafting between 1990 and 1994. Women were older, had higher preoperative prevalences of urgent operation because of unstable angina, diabetes, peripheral vascular disease, hypertension, and single-vessel coronary artery disease (p < 0.0001), and a lower prevalence of left ventricular ejection fraction 40% or less (p < 0.0001). The prevalences of operative mortality (men, 1.8%; women, 3.5%), low-output syndrome (men, 6.6%; women, 14.8%), and myocardial infarction (men, 2.8%; women, 5.5%) were higher in women (p < 0.0001). Patients were divided into quartiles for body surface area, weight, height, and body mass index. For both men and women, there was no difference in operative mortality between the highest and lowest quartiles of body size. Women, however, had a higher prevalence of operative mortality than men in the lower quartiles of body surface area, height, and weight and in the higher quartiles of body mass index. Among men, the prevalence of low-output syndrome increased (p < 0.0001) with decreasing body surface area, weight, and body mass index, suggesting that body size did influence the prevalence of low-output syndrome. However, women had a higher prevalence of low-output syndrome than men in every category and quartile of body size (p < 0.0001). Multivariable analysis identified gender as a significant determinant of operative mortality (odds ratio 1.83, 95% confidence interval 1.27 to 2.64) and low-output syndrome (odds ratio 2.52, 95% confidence interval 2.05 to 3.11). When multivariable adjustments were made for body size and preoperative risk factors, gender remained a predictor of both operative mortality and low-output syndrome. Multivariable assessment of risk for men and women separately identified that urgent operation was a predictor of operative mortality (odds ratio 2.52, 95% confidence interval 1.32 to 5.61) and low-output syndrome (odds ratio 1.57, 95% confidence interval 1.14 to 2.17) in women but not men. In conclusion, the increased risk of coronary artery bypass grafting in women may be explained in part by dramatic differences in preoperative risk factors between men and women. In both men and women, small body size did not increase the risk of operative mortality, but may have contributed to the risk of low-output syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1995

Repair of the aortic valve in patients with aortic insufficiency and aortic root aneurysm.

Patients with aneurysms of the ascending aorta or aortic root frequently have aortic insufficiency despite normal aortic leaflets. The aortic valve dysfunction is caused by dilatation of the sinotubular junction, distortion or dilatation of the sinuses of Valsalva, annuloaortic ectasia, or a combination of these problems. In the case of annuloaortic ectasia, reconstruction of the aortic root is performed by reimplanting the aortic valve in a tubular Dacron graft (reimplantation). In the case of mild or no annuloaortic ectasia, reconstruction of the aortic root is performed by correcting the dilated sinotubular junction and replacement of the aortic sinuses if they are also dilated with an appropriately tailored Dacron graft (remodeling). From July 1989 to March 1994, 45 patients have had either reimplantation of the aortic valve (19 patients) or remodeling of the aortic root (26 patients). Fourteen patients had Marfan's syndrome, 11 had acute and five had chronic type A aortic dissection, and nine also had transverse arch aneurysm. There were two operative deaths, both in the remodeling group. One patient who had reimplantation needed composite replacement of the aortic valve and ascending aorta because of persistent aortic insufficiency after the repair. A young patient with Marfan's syndrome had progressive aortic valve dysfunction during a growth spurt and had aortic valve replacement 2 years after the initial operation. No other valve-related complication has occurred. The remaining 41 patients have only mild or no aortic insufficiency, and the repair remains stable from 1 to 58 months, mean 18 months. These two types of aortic valve reconstruction have provided excellent clinical results in carefully selected adult patients.

Adult↗
PubMed1995

Follow up of patients after valvular surgery: mail vs. telephone.

A study was undertaken to compare the results of patient follow up done by mail and by telephone. Using valve follow up questionnaires recently received by mail, 100 patients were randomly selected from this group for further follow up by telephone. Interviews were conducted while blinded to the mail response. Patients were questioned as to their functional status (NYHA), improvement as a result of surgery (IMP), incidence of reoperation (REOP) or bacterial endocarditis (SBE) and thromboembolic complications (TE). They were also asked whether they would prefer future follow up by mail or telephone. Analysis using the kappa coefficient and McNemar's test revealed a difference (p < 0.001) in NYHA when comparing mail and telephone responses but no difference in either IMP or TE. There was no incidence of REOP or SBE. Sixty-six percent of patients had no preference in type of future follow up and of the remaining 33%, two-thirds preferred to be contacted by phone. It appears that NYHA is significantly overestimated by the patient whereas the two methods of follow up are comparable when assessing IMP and TE. It should be noted, however, that patients seem to have difficulty in identifying the occurrence of TE and in differentiating between stroke and TIA.

Activities of Daily Living↗
PubMed1995

The surgical treatment of patients with prosthetic valve endocarditis.

Prosthetic valve endocarditis is associated with high mortality and morbidity. Although antibiotics alone may sterilize an infected prosthetic valve, adjunctive surgical therapy is often necessary. Depending on the virulence of the offending microorganism, the type of prosthetic valve and the site where it was implanted, the infection spreads into paravalvular structures, producing abscess. Systemic embolization of infected material may cause metastatic abscess. Thus, timing of surgery in these patients is crucial to optimize clinical results. An aggressive approach is justifiable in most patients with prosthetic valve endocarditis. It is believed that radical resection of all infected material and reconstruction of the heart and annuli with fresh autologous or glutaraldehyde-fixed bovine pericardium offer the best chance to eradicate the infection. Prolonged antibiotic therapy is also necessary in these patients. In the author's personal experience with 45 patients with prosthetic valve endocarditis, the infection was limited to the valve in 10 patients and had extended into the surrounding tissues in 35. The operative mortality rate was 13%. The actuarial survival at 5 years was 61% +/- 5%. These results support the premise that radical resection of all infected materials offers a good chance for curing prosthetic valve endocarditis.

Abscess↗
PubMed1994

Stentless porcine bioprosthesis for aortic valve replacement.

We report herein our experience with the Toronto Stentless Porcine Valve (Toronto SPV, manufactured by St. Jude Medical Inc., Minneapolis, MN, USA) for aortic valve replacement (AVR). To date 146 SPV valves have been implanted, 29 in an initial clinical trial (from October 1987 to April 1987) and 117 in the current FDA trial (September 1991 to January 1994). In the current trial the majority of patients were male (76%), aortic stenosis was the dominant lesion (73%) and 68% of the patients received a valve size 27 mm or greater. The mean age was 61.3 +/- 12.0 years. For the entire group there has been no hospital death and no patient has required a pacemaker. Perioperative complications were myocardial infarction in three patients and suspect subacute bacterial endocarditis (medically treated) in three patients. There have been two late deaths (2%), two patients have had transient ischemic attacks (2%), and one patient suffered stroke with complete neurological recovery (1%). To date there has been no case of primary valve failure. Echocardiographic assessment of the SPV valve has demonstrated excellent effective valve orifice areas with very low transvalvular gradients and 95% of the patients had either 0 or 1+ insufficiency. These results are encouraging and justify the continued use of this valve in clinical trials. Further follow-up is required to determine its durability.

Adult↗
PubMed1992

Operative risks and long-term results of operation for left ventricular aneurysm.

A review of 336 consecutive patients who underwent repair of left ventricular aneurysm from 1978 to 1989 disclosed that partial resection of the aneurysm and conventional closure of the ventriculotomy was performed in 281 patients, inverted T closure in 17, and endocardial patch in 38. These two latter techniques were developed in an attempt to restore normal left ventricular geometry. The operative mortality was 6.8% (23 patients). A stepwise logistic regression analysis of various preopeative clinical, hemodynamic, and angiographic variables revealed that left ventricular ejection fraction of 0.20 or less, age greater than 60 years, previous myocardial revascularization, lack of angina, and New York Heart Association functional class IV were independent predictors of operative mortality. The technique of repair was not a predictor of outcome, but when patients with poor left ventricular function were analyzed separately, the operative mortality was reduced from 12.5% to 6.5% when newer techniques were employed. Patients were followed up during a mean of 6.3 years. There have been 51 late deaths, 45 cardiac. Cox regression analysis indicated that poor left ventricular function and left main coronary artery stenosis were the only two predictors of late mortality. The actuarial survival at 10 years was 63% +/- 4%. Most patients (88%) are in New York Heart Association class I or II. These data indicate excellent long-term results after repair of left ventricular aneurysm. Newer techniques of repair are valuable in patients with poor left ventricular function.

Actuarial Analysis↗
PubMed1992

Clinical and hemodynamic assessment of the Hancock II bioprosthesis.

The Hancock II bioprosthesis was used for heart valve replacement in 614 patients from 1982 to 1990. Aortic valve replacement (AVR) was performed in 376 patients, mitral valve replacement (MVR) in 195, and aortic and mitral valve replacement (DVR) in 43. The mean age was 62.7 years, and 78% of all patients were in New York Heart Association functional class III or IV before operation. Coronary artery bypass graft was necessary in 232 patients and replacement of ascending aorta in 55. There were 31 operative deaths (AVR, 4%; MVR, 6%; DVR, 9%). Follow-up was complete in 98.5% of the patients and extended from 12 to 103 months, with a mean of 49 months. At the last follow-up, 85% of the patients were in New York Heart Association class I or II. The actuarial survival at 8 years was 79% +/- 3% for AVR, 68% +/- 4% for MVR, and 65% +/- 10% for DVR. The freedom from stroke at 8 years was 93% +/- 2% for AVR, 83% +/- 5% for MVR, and 90% +/- 5% for DVR. At the end of 8 years 96% +/- 1% of all patients were free from endocarditis, 92% +/- 1% were free from primary tissue failure, and 89% +/- 3% were free from reoperation. The actuarial freedom from valve-related death at 8 years was 98% +/- 1% for AVR, 86% +/- 5% for MVR, and 91% +/- 6% for DVR. Hemodynamic assessment was obtained by Doppler echocardiography in all operative survivors and demonstrated satisfactorily effective valve orifices and transvalvular gradients. The clinical results obtained with the Hancock II bioprosthesis have been gratifying, particularly in the aortic position. This bioprosthesis is our biological valve of choice.

Actuarial Analysis↗
PubMed1992

Aortic valve replacement with the Toronto SPV bioprosthesis.

The Toronto SPV is a Dacron covered stentless porcine aortic prosthesis used for aortic valve replacement (AVR). We implanted this valve in 53 patients with a mean age of 58 years. The predominant valve lesion was aortic stenosis in 39 patients, insufficiency in 13 and a failed bioprosthesis in one. Six patients also had mitral valve disease and 18 had coronary artery disease. There was one operative death. Patients have been followed for four to 58 months, mean 27 months. There have been two late deaths but neither one was valve related. The actuarial survival at four years was 92% +/- 5%. Two patients required reoperation for reasons other than failure of the stentless aortic valve. There have been no thromboembolic complications. No patient had had infective endocarditis. Doppler echocardiographic assessment of the stentless valve revealed excellent effective valve areas and low transvalvular gradients. A few patients developed mild aortic insufficiency after implantation of the valve, but this problem has been practically eradicated by correct sizing of the prosthesis. AVR with the Toronto SPV provides excellent functional and hemodynamic results. This bioprosthesis seems to be associated with an extremely low rate of valve related complications. These findings justify its continued use, but further follow up is needed to determine its durability.

Adult↗
PubMed1992

An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta.

A number of patients who require an operation for complications of annuloaortic ectasia, such as aortic incompetence or aneurysm of the aortic root (or both), have normal aortic valve leaflets. We have treated these patients by excising the aneurysmal portion of the ascending aorta and sinuses of Valsalva but by leaving the aortic valve leaflets and some arterial wall attached to the left ventricular outflow tract. The aortic valve is reimplanted inside a collagen-impregnated tubular Dacron graft, similar to what is done for implantation of an aortic valve homograft. The coronary arteries are also reimplanted. This operation was performed in 10 patients. All patients had annuloaortic ectasia and five had the stigmata of Marfan syndrome. Four patients had acute aortic dissection. There were no operative deaths, but one patient required composite replacement of the aortic valve and ascending aorta because of persistent aortic incompetence. Postoperative Doppler echocardiography revealed normal aortic valve function in six patients and mild incompetence in three. The preliminary results of this new operation are encouraging. Further investigation is necessary to establish the best size, shape, and type of material that should be used to replace the aortic root while preserving the aortic valve.

Adult↗
PubMed1992

Coronary artery bypass grafting in patients with poor ventricular function. Cardiovascular Surgeons of the University of Toronto.

Although patients with severe ventricular dysfunction have improved long-term survival times after coronary bypass procedures, operative morbidity and mortality rates remain high. This study was designed to identify the contemporary risk factors for isolated coronary artery bypass grafting in this high-risk subgroup. Between January 1982 and December 1990, a total of 12,471 patients underwent isolated coronary artery bypass grafting. The 9445 patients with preoperative ejection fractions greater than 40% had a lower operative mortality rate (2.3%) than that of the 2539 patients with ejection fractions between 20% and 40% (4.8%) and that of the 487 patients with ejection fractions less than 20% (9.8%; p less than 0.001). However, patients with ejection fractions of less than 20% were demographically distinct from those with higher ejection fractions. This group was older, with fewer women, a higher frequency of left main stenosis, and more frequent requirement of urgent operation for unstable angina. The risk factors for operative death also varied with preoperative ejection fraction. The traditionally accepted risk factors--urgency of operation, left main coronary artery stenosis, reoperation, sex, and age--were predictive of risk of operative death for patients with ejection fractions greater than 40%. The risk of operative death for patients with ejection fractions between 20% and 40% was predicted by urgency of operation, reoperation, sex, myocardial protection, and age. The only predictor of risk of operative death for patients with ejection fractions less than 20% was urgency of operation. Patients undergoing isolated coronary artery bypass grafting who have severe ventricular dysfunction are therefore a highly selected, high-risk subgroup of patients who risk depends on the urgency of operation. Strategies to improve the results in these patients should be focused on patient selection, improvement of myocardial protection, and more aggressive preoperative treatment of myocardial ischemia.

Age Factors↗
PubMed1991

Current risk of coronary bypass for unstable angina.

The risk associated with surgical revascularization for unstable angina is critically dependent upon the clinical presentation of the patient. For this study, between January 1982 and December 1987, clinical, angiographic, operative and hospital outcome data were collected prospectively for 6539 patients undergoing surgery for unstable angina. Urgent surgery was performed in 1523 patients (23.3%), while 5016 (76.7%) underwent semielective revascularization. The mean age was 58.9 +/- 9.2 years and 805 patients (12.3%) were aged 70 years or above. The male:female ratio was 3.6:1. Depressed left ventricular function (left ventricular ejection fraction less than 40%) was present in 27.2% of the population. Preoperative myocardial infarction (within 30 days of surgery) had occurred in 588 patients (9.0%). Operative mortality was 4.6% (301 deaths). Stepwise logistic regression analysis was performed to determine the independent predictors of operative mortality. The following variables were selected in descending order: urgent surgery (P less than 0.001), coronary reoperation (P less than 0.001), depressed left ventricular (P less than 0.001), female gender (P less than 0.001), increasing age (P less than 0.001), left main stenosis (P = 0.002), and preoperative myocardial infarction (P less than 0.001). Predicted operative mortality varied between 0.5 +/- 0.3% and 82.6 +/- 12.7%. The most important determinant for patients with a preoperative myocardial infarction was left ventricular dysfunction, whereas urgent surgery for unstable angina was the most important risk variable in those without preoperative necrosis.

Adult↗
PubMed1991

Recent preoperative myocardial infarction increases the risk of surgery for unstable angina.

Patients with postinfarction angina undergoing surgery for unstable angina face an increased risk of operative mortality. Between January 1982 and December 1987, clinical, angiographic, and operative data was collected prospectively in 588 unstable patients with a prior myocardial infarction within 30 days of surgery (MI) and 5951 unstable patients without preoperative damage (NONMI). MI patients were characterized as being older (age greater than or equal to 70 years: MI, 19.7%; NONMI, 11.6%; p less than 0.001) and having more left ventricular dysfunction (left ventricular ejection fraction less than 40%: MI, 34.8%; NONMI, 26.4%; p less than 0.001). Semi-elective surgery was performed in 82.0% of NONMI patients while 76.9% of MI patients underwent urgent surgery. Operative mortality was increased in MI patients (MI, 11.1%; NONMI, 4.0%; p less than 0.001) which was related to the extent of preoperative MI (non-Q wave, 8.3%; Q wave, 17.5%; p less than 0.001). Stepwise logistic regression analysis identified preoperative MI as an independent risk variable of operative mortality for unstable angina. Separate multivariate analyses were performed to identify the independent predictors for MI and NONMI patients. The multivariate predictors of operative death for MI patients were left ventricular dysfunction, reoperative coronary surgery, nonuse of the internal mammary, age, transmural MI (relative risk 2.11 vs non-Q wave infarction) and left main stenosis. For NONMI patients, the independent variables were urgent operation, left ventricular dysfunction, reoperation, female gender, left main stenosis, and age. The results of this study indicate that recent preoperative MI adversely influences the surgical results in patients with unstable angina. Alternative treatment strategies are warranted for high risk patients, particularly those with transmural MIs and impaired ventricular function.

Adult↗