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Biomedical subjects

T E David

Publications and source records attributed to T E David.

At least 73 records · Page 4Linked to original sources
PubMed1997

Aortic root aneurysms: remodeling or composite replacement?

BACKGROUND: Patients with ascending aortic aneurysms often have aortic insufficiency due to dilatation of the aortic root. Although composite replacement of the aortic valve and ascending aorta has been the standard treatment, an aortic valve-sparing operation is feasible in patients with normal aortic valve leaflets. METHODS: From 1988 to 1996, 208 patients with ascending aortic aneurysms and aortic insufficiency were operated on. Aortic valve-sparing operations were performed in 101 patients: 70 men and 31 women with a mean age of 53 years (range, 14 to 82 years). Twenty-eight patients had the stigmata of Marfan's syndrome. Fifteen patients had acute and 8 had chronic type A aortic dissection. Coronary artery disease was detected in 19 patients and mitral regurgitation in 5. Two types of aortic valve-sparing operations were performed: remodeling of the aortic root with preservation of the aortic valve in 73 patients and reimplantation of the aortic valve in a tubular Dacron graft in 28. Patients were followed up from 3 to 108 months (mean, 31 months). Doppler echocardiographic studies were performed annually. RESULTS: There were two operative deaths. One patient had to have aortic valve replacement because of persistent aortic insufficiency. There were five late deaths; the actuarial survival rate at 6 years was 87% +/- 5%. One patient required aortic valve replacement 2 years after the initial operation; the freedom from aortic valve replacement at 6 years was 97% +/- 2%. There have been no thromboembolic or infective complications. Only 3 patients have moderate aortic insufficiency; the remaining patients have mild or no aortic insufficiency. CONCLUSIONS: The midterm results of aortic valve-sparing operations have been excellent and justify their continued use in patients with aortic root aneurysms and normal or near-normal aortic valve leaflets.

Adolescent↗
PubMed1997

Aortic and mitral valve replacement with reconstruction of the intervalvular fibrous body.

OBJECTIVE: The intervalvular fibrous body between the aortic and mitral valves can be damaged by infective endocarditis, degenerative calcification, or multiple previous heart valve operations, making double valve replacement difficult. We have managed this problem by approaching the aortic and mitral valves through the aortic root and the dome of the left atrium. After excising the aortic valve, the diseased fibrous body, and the mitral valve, we suture a properly tailored patch of Dacron fabric or bovine pericardium to the lateral and medial fibrous trigones and to the aortic root, reestablishing the aortic and mitral anuli. A prosthetic mitral valve is implanted and a separate patch is used to close the left atriotomy before implantation of a prosthetic aortic valve. This study was undertaken to determine the efficacy of this operation. METHODS: Forty-three patients underwent reconstruction of the intervalvular fibrous body during aortic and mitral valve replacement because of infective endocarditis with abscess in 14 patients, extensive calcification in 9, lack of fibrous tissue because of multiple previous operations in 10, and to enlarge the aortic and mitral anuli in 10. The group comprised 18 men and 25 women with a mean age of 58 +/- 12 years. Thirty-two patients had had one or more previous heart valve replacements. All patients were in New York Heart Association functional classes III and IV, and 9 patients were in shock before the operation. RESULTS: Seven operative deaths occurred (16%). Early prosthetic valve endocarditis developed in two patients and necessitated reoperation. Follow-up extended from 4 to 108 months, with a mean of 38 months. No patient was lost to follow-up. Six late deaths occurred. The actuarial survival at 6 years was 56% +/- 6%. A Doppler echocardiographic study revealed normal prosthetic valve function and anatomically intact anuli in all 30 long-term survivors. CONCLUSIONS: Reconstruction of the intervalvular fibrous body during aortic and mitral valve replacement is a satisfactory operative approach in patients with complex valve annular pathology.

Animals↗
PubMed1997

Long-term results of surgery for active infective endocarditis.

OBJECTIVE: This paper was undertaken to determine the long-term outcome of active infective endocarditis treated with antibiotic and radical excision of infected tissues by surgery. METHODS: From October 1978 to August 1994, 122 consecutive patients were operated on during the acute phase of infective endocarditis. There were 85 men and 37 women whose mean age was 50 years, ranging from 20 to 79. Surgery was needed because of one or more of the following complications: cardiogenic/septic shock in 19 patients, congestive heart failure in 68, persistent sepsis in 64, peripheral embolization in 20, and cerebral embolization in 10. The offending microorganism was identified in 110 patients, staphylococci were the most common ones. Seventy-six patients had native valve endocarditis and 46 had prosthetic valve endocarditis. Simple valve replacement or repair was performed in 60 patients and radical resection of the valve and surrounding tissues with reconstruction of the heart with either fresh autologous pericardium or glutaraldehyde-fixed bovine pericardium was performed in 62 with paravalvular abscess. Pulmonary autograft and aortic homograft were used in only three patients, the remaining patients had either bioprostheses or mechanical heart valves if valve repair was not feasible. RESULTS: There were nine deaths, for an operative mortality of 7.4%. Logistic regression analysis identified preoperative shock and renal failure as predictors of operative mortality. Operative survivors were followed up from 4 to 173 months, mean of 56.4. The actuarial survival at 10 years was 61 +/- 6%. Logistic regression analysis identified preoperative New York Heart Association functional class IV and perioperative renal failure as predictors of late mortality. Eight patients developed recurrent endocarditis 10-102 months postoperatively. The freedom from recurrent endocarditis at 10 years was 79 +/- 9%. All patients who developed this late complication had paravalvular abscess at the time of original operation. CONCLUSIONS: These data suggest that surgery for active infective endocarditis yield a high probability of eradicating the infection with relatively low operative mortality and good long-term results.

Abscess↗
PubMed1997

Aortic valve-sparing operations in patients with ascending aortic aneurysms.

Composite replacement of the aortic valve and ascending aorta was the standard treatment for patients with aortic insufficiency and aortic root aneurysm. However, it has been pointed out that the aortic valve leaflets are normal or near normal in almost one half of the patients who undergo surgery for aortic root aneurysms. It is now possible to accurately determine the quality of the aortic valve leaflets using transesophageal multiplane echocardiography, and with current knowledge of the functional anatomy of the aortic root, it is feasible to reconstruct the aortic root and preserve the aortic valve leaflets in these patients. There are various aortic valve-sparing procedures depending on the mechanism of aortic insufficiency and the pathology of the aortic root. Although these operations are now performed in many cardiac centers, long-term results are not yet available. Aortic valve-sparing operations have been performed in 97 patients in our institution since 1988; the clinical results have been excellent and the valve repair remains stable for up to 8 years of follow-up. These results justify the continued use of these operative procedures.

Aorta↗
PubMed1997

Incidental detection of an aortic valve papillary fibroelastoma by echocardiography in an asymptomatic patient presenting with hypertension.

Papillary fibroelastomas are rare, frond-like tumours of uncertain etiology seen on cardiac valves, uncommonly found antemortem. They carry a significant risk of embolization, making their detection and excision during life an important issue. A case of an aortic valve papillary fibroelastoma is described, which was found at echocardiography in a patient being assessed for previously unrecognized, severe hypertension.

Aortic Valve↗
PubMed1996

Changing pattern of valve surgery.

BACKGROUND: Advances in surgical technique and perioperative myocardial protection have reduced the risk of aortic and mitral valve surgery. Improved methods of valve repair have reduced the proportion of patients who require valve replacement. However, patients who require valve replacement often have advanced disease and/or extensive calcification and may therefore be at increased risk for perioperative morbidity and mortality. METHODS AND RESULTS: We reviewed the results of 2898 patients who underwent aortic (AVR) or mitral (MVR) valve replacement at the Toronto Hospital. We compared patients who underwent surgery between January 1982 and December 1986 (early group) with those who were operated on between January 1989 and December 1993 (late group). The univariable and multivariable predictors of postoperative low-output syndrome (LOS) and operative mortality (OM) were determined for each time period. A total of 1779 patients underwent AVR (late, n = 997; early, n = 782). Multivariable analyses revealed that the late group had significantly more patients with independent pre-epidemiology operative risk factors for both OM and LOS. Despite the greater proportion of high risk patients, the incidence of postoperative LOS was lower in the late group (10% versus early, 14%; P = .012). There was no difference in OM between the two groups (late, 3.4% versus early, 3.7%; P = .732). A Total of 1119 patients underwent MVR (late, n = 493; early, n = 626). Compared with the early group, the late group had significantly more patients with preoperative multivariable risk factors for OM and LOS. There was no difference in postoperative LOS (late, 19% versus early, 21%; P = .361) or OM between the two groups (late, 5.8% versus early, 6.9%; P = .432). CONCLUSIONS: Despite an increase in high-risk patients, there was no significant increase in mortality or morbidity associated with aortic or mitral valve surgery.

Adult↗
PubMed1996

Results of represervation of the chordae tendineae during redo mitral valve replacement.

BACKGROUND: Previous studies have shown that preservation of the chordae tendineae improves early and late postoperative left ventricular function after mitral valve replacement. This report describes the results of represervation of the chordae tendineae during redo mitral valve replacement in patients who had their chordae tendineae preserved during their initial operation. METHODS: Fifty-four patients undergoing reoperative mitral valve replacement with preservation of their chordal annular attachments (chordae group) were compared with 187 patients who had redo mitral valve replacement without preservation of the chordae (nonchordae group). The interval between the initial operation and the reoperation was 8.7 +/- 4.4 years in the chordae group and 8.6 +/- 4.9 years in the nonchordae group (p = 0.315). Seventy-three patients underwent aortic valve replacement during their redo mitral valve replacement compared with 168 patients who had mitral valve replacement alone. There were 15 patients who had their chordal attachments represerved during redo double-valve replacement. RESULTS: In the chordae group, intraoperative assessment revealed excellent chordal connection between the preserved papillary muscles and the mitral annulus in all patients. One patient had adhesions between the preserved chordae and the stent of the tissue valve. The chordal attachments were preserved during insertion of the second valve in all patients. The incidence of low output syndrome and operative mortality in the chordae group was 16.7% and 7.4%, respectively. In the nonchordae group, the incidence of low output syndrome was 27.3% (p = 0.112 compared with the chordae group) and the operative mortality was 13.4% (p = 0.236 compared with the chordae group). In patients with double-valve replacement, represervation of the chordae was associated with a reduction in low output syndrome (0% versus 24%; p = 0.034) and mortality (6.7% versus 15.5%; p = 0.374). CONCLUSIONS: Preservation of the chordal attachments between the papillary muscles and the mitral annulus can be accomplished during reoperative mitral valve replacement. Represervation of the chordae tendineae may reduce postoperative low output syndrome, especially in high-risk patients undergoing redo double-valve replacement.

Aortic Valve↗
PubMed1996

Long-term results of operation for paravalvular abscess.

BACKGROUND: Operation for infective endocarditis with paravalvular abscess is reportedly associated with high mortality and morbidity rates. In an attempt to improve surgical outcome, an approach of radical resection of the abscess and inflamed tissues and reconstruction of the heart with either fresh or glutaraldehyde-fixed bovine pericardium was adopted by two surgeons at our institution. METHODS: From 1979 to 1995, 70 consecutive patients with active infective endocarditis and paravalvular abscess underwent operation. Their mean age was 49 years (range, 16 to 75 years), and 50 patients (71%) were men. Thirty-four patients had native and 36 had prosthetic valve endocarditis (8 had had composite replacement of the aortic valve and ascending aorta). Most patients (78%) were in New York Heart Association functional class IV. The principal indication for operation was cardiogenic or septic shock in 11 patients, or one or more of the following: persistent sepsis despite adequate antibiotic therapy in 36, congestive heart failure in 31, and recurrent emboli in 16. Staphylococci were responsible for the infection in 37 patients (53%). The abscess was in the mitral annulus in 11 patients, in the aortic root in 44, and in the aortic root and at least one other annulus in 15. After wide resection of the abscess, we reconstructed the heart and annuli with autologous or bovine pericardium. Mechanical heart valves were implanted in 36 patients, bioprostheses in 30, and aortic homografts in 2; valve repair was possible in 2. Sixteen patients required composite replacement of the ascending aorta and aortic valve. RESULTS: There were 9 operative deaths (13%). Infections caused by staphylococci and infections in multiple annuli were associated with increased operative mortality rates. Only 1 patient had persistent infection and required reoperation. The mean follow-up was 56 +/- 40 months. There were 12 late deaths, mostly cardiac. The actuarial survival including operative deaths was 64% +/- 8% at 8 years. In 8 patients, recurrent infective endocarditis developed 10 to 102 months after operation. The freedom from recurrent endocarditis was 76% +/- 10% at 8 years. CONCLUSIONS: This experience indicates that radical resection of the abscess and reconstruction of the heart with pericardium yield an excellent chance of eradicating the infection in patients with infective endocarditis and paravalvular abscess. The type of valve implanted may not be as important as radical resection of the abscess. These patients appear to have a greater than average risk of recurrent endocarditis.

Abscess↗
PubMed1996

Mechanical valves.

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Anticoagulants↗
PubMed1996

Hemodynamic benefits of the Toronto Stentless Valve.

We report on 254 consecutive patients (170 male, 84 female) undergoing aortic valve replacement with the Toronto SPV Stentless Valve (St. Jude Medical, Inc., St. Paul, Minn.). Mean age (+/- standard deviation) was 62.1 +/- 11.6 years. Three patients (1%) received sizes 21 or 22 mm, 24 (9%) received size 23 mm, and 227 patients (89%) received sizes 25, 27, or 29 mm. Serial echocardiography was used to assess valve performance during a 3-year follow-up. Mean gradient decreased by 35.8% (p < 0.0001; 95% confidence interval -39.6%, -31.7%) from postoperative values to the 3- to 6-month follow-up and by 6.1% (p = 0.004; 95% confidence interval -10.1%, -2%) at each subsequent interval; effective orifice area increased by 17.2% (p = 0.0001; 95% confidence interval 12.0%, 22.6%) initially and by 4.4% (p < 0.001; 95% confidence interval 1.8%, 7.0%) thereafter. At 2 years of follow-up, mean gradient was 3.3 +/- 2.1 mm Hg and mean effective orifice area was 2.2 +/- 0.8 cm2. Studies on left ventricular mass were carried out on 84 patients. Left ventricular mass decreased by 14.3% (37.8 +/- 57.9 gm; p < 0.0001; 95% confidence interval -53.7, -21.9 gm) and left ventricular mass index decreased by 15.2% (21.1 +/- 30.5 gm/m2; p < 0.0001; 95% confidence interval -29.5, -12.7 gm/m2) from postoperative values to the 3- to 6-month follow-up interval. The reduction in residual gradient and potential regression in left ventricular hypertrophy may have a beneficial prognostic implication. We believe that the unique stentless design of the Toronto SPV Stentless Valve allows this to occur.

Actuarial Analysis↗
PubMed1996

Geometric mismatch of the aortic and pulmonary roots causes aortic insufficiency after the Ross procedure.

BACKGROUND: Geometric mismatch between the two semilunar valves can cause aortic insufficiency after the Ross procedure. Thus, whenever the aortic root is larger than the pulmonary root, surgical reduction of the aortic anulus or of the sinotubular junction (or both) to match the diameters of the pulmonary root is necessary to prevent late malfunction of the pulmonary autograft. METHODS: The Ross procedure was performed in 81 patients during the past 5 years. The diameters of the aortic and pulmonary roots were measured in 77 patients. Reduction of the aortic anulus and of the sinotubular junction was necessary in 27 patients, reduction of the aortic anulus alone in 12, and reduction of the sinotubular junction alone in 10. The pulmonary autograft was implanted in the subcoronary position in the aortic root in two patients, as a complete root replacement in 58, and as an inclusion root in 21. RESULTS: There was one operative death, caused by myocardial infarction. Aortic insufficiency developed in one patient who did not have measurement and reduction of the aortic anulus, and aortic root replacement was necessary 2 weeks later. Patients have been followed up from 2 to 64 months (mean 15 months). Two patients have required late reoperations: one because of pulmonary artery stenosis and the other because of a false aneurysm between the autograft and the mitral valve. The most recent Doppler echocardiographic study shows that 90% of the patients have only trace or no aortic insufficiency, and 10% have mild aortic insufficiency. CONCLUSION: This experience suggests that adjustment of the diameter of the aortic anulus or of the sinotubular junction of the aorta may be important to prevent aortic insufficiency after the Ross procedure.

Adolescent↗
PubMed1996

Predictors of low cardiac output syndrome after coronary artery bypass.

The purpose of this study was to identify patients at risk for the development of low cardiac output syndrome after coronary artery bypass. Low cardiac output syndrome was defined as the need for postoperative intraaortic balloon pump or inotropic support for longer than 30 minutes in the intensive care unit to maintain the systolic blood pressure greater than 90 mm Hg and the cardiac index greater than 2.2 L/min per square meter. The preoperative patient characteristics that were independent predictors of low cardiac output syndrome were identified among 4558 consecutive patients who underwent isolated coronary artery bypass at The Toronto Hospital between July 1, 1990, and December 31, 1993. The overall prevalence of low cardiac output syndrome was 9.1% (n = 412). The operative mortality rate was higher in patients in whom low cardiac output syndrome developed than in those in whom it did not develop (16.9% versus 0.9%, p < 0.001). Stepwise logistic regression analyses identified nine independent predictors of low output syndrome (percent frequency in parentheses) and calculated the factor-adjusted odds ratios associated with each predictor: (1) left ventricular ejection fraction less than 20% (27%, odds ratio 5.7); (2) repeat operation (25%, odds ratio 4.4); (3) emergency operation (27%, odds ratio 3.7); (4) female gender (16%, odds ratio 2.5); (5) diabetes (13%, odds ratio 1.6); (6) age older than 70 years (13%, odds ratio 1.5); (7) left main coronary artery stenosis (12%, odds ratio 1.4); (8) recent myocardial infarction (16%, odds ratio 1.4); and (9) triple-vessel disease (10%, odds ratio 1.3). Low cardiac output syndrome is a clinical outcome that may result from inadequate myocardial protection or perioperative ischemic injury. Patients at high risk for the development of low cardiac output syndrome should be the focus of trials of new techniques of myocardial protection to resuscitate the ischemic myocardium.

Aged↗
PubMed1996

Replacement of chordae tendineae with Gore-Tex sutures: a ten-year experience.

BACKGROUND AND AIMS OF THE STUDY: Expanded polytetrafluoroethylene sutures have been used for the replacement of chordae tendineae of the mitral valve since 1985 at The Toronto Hospital. This study examines the long term results of mitral valve repair with chordal replacement with this material. MATERIALS AND METHODS: From July 1985 to December 1993, 134 consecutive patients with mitral regurgitation due to degenerative disease of the mitral valve underwent mitral valve repair with replacement of elongated or ruptured chordae tendineae with one to six (mean of 2.8) Gore-Tex sutures. The patients' mean age was 61 years, range 22-86. In addition to mitral valve repair, 14 patients underwent aortic valve surgery, three underwent replacement of the ascending aorta, six underwent tricuspid valve repair, nine underwent the maze procedure for atrial fibrillation, and 13 underwent coronary artery bypass. The patients were followed for between 20 and 116 months, mean 51 months. No patient has been lost to follow up. RESULTS: There were one operative and eight late deaths. The actuarial survival at eight years was 88% +/- 6%. Four patients required reoperation, one for persistent hemolysis and three for recurrent mitral regurgitation. The Gore-Tex chordae were not responsible for the reoperation in any patient. The freedom from reoperation at eight years was 96% +/- 2%. CONCLUSIONS: Expanded polytetrafluoroethylene sutures are excellent for chordal replacement during mitral valve repair and do not fail during the first decade following surgery. This material has allowed us to increase the probability of successful mitral valve repair in patients with degenerative disease of the mitral valve and prolapse of both leaflets.

Adult↗
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↗