Biomedical subjects

T E David

Publications and source records attributed to T E David.

At least 55 records · Page 3Linked to original sources

PubMed1999

Aortic valve replacement with stentless porcine aortic valve: a pioneer series.

Durability of stentless porcine aortic valves is determined by the resistance of the cusps to mechanical fatigue and reactions by the host. This study examines the role of mismatch between the size of the valve and the diameter of the sinotubular junction on durability of the valve. A custom-made stentless porcine aortic valve designed for implantation in the subcoronary position was used for aortic valve replacement in 29 patients. There were 15 men and 14 women, with a mean age of 58 years (range 26 to 72 years). In addition to aortic valve replacement, 6 patients had mitral valve surgery, 10 patients had coronary artery bypass graft, 1 patient had closure of an atrial septal defect, and 1 had concomitant aortobi-iliac bypass graft. Follow-up time extended from 10.3 to 11.5 years and was complete. The selection of size of valve implanted was based solely on the diameter of the aortic annulus. Because the diameter of the sinotubular junction plays an important role in leaflet motion and valve competence, the size of valves was compared with the diameter of the sinotubular junction of the aortic roots where they were implanted. There was one operative death and five late deaths. There were no valve-related deaths. The actuarial survival at 10 years was 76%+/-5%. There were only two transient ischemic attacks and no strokes. One patient developed endocarditis 4 years' postoperatively and was successfully treated with aortic valve re-replacement. One patient with cardiomyopathy had heart transplantation. Thus, the stentless valve was at risk of failure in 21 patients. Nine patients developed echocardiographic evidence of valve dysfunction: seven had aortic valve re-replacement and two continue to be observed because the dysfunction is not severe. The function of the stentless valve remained normal in 12 patients. Patients with bioprosthetic valve dysfunction had a sinotubular junction 3.2+/-1.3 mm larger than the size of the valve, whereas patients with normal bioprosthetic valve function had a sinotubular junction 0.8+/-1.2 mm larger than the size of the valve (P = .01). The durability of stentless porcine aortic valve implanted in the subcoronary position is affected by discrepancies in diameters between the xenograft valve and the sinotubular junction of the aortic root. Sinotubular junction greater than the size of the stentless valve probably increases mechanical stress on the cusps and causes premature valve failure.

Adult↗

PubMed1999

The Toronto SPV: hemodynamic data at 1 and 5 years' postimplantation.

The Toronto-SPV (T-SPV) bioprosthesis has been used for aortic valve replacement (AVR) since July 1991. There is no published data on its mid-term hemodynamic performance. This study compares the hemodynamic data of a consecutive series of patients at 1 and 5 years after AVR. The first 109 consecutive patients who had AVR with a T-SPV have been monitored for a minimum of 5 years and have had annual Doppler echocardiographic studies. There were 80 men and 29 women in the study; mean age was 62 years (range 34 to 80 years). Concomitant coronary artery bypass surgery was done in 35 patients. One operative and nine late deaths occurred. The mean systolic gradient across the T-SPV in all patients was 3.9+/-2.4 mm Hg at 1 year and 4.1+/-3.3 mm Hg at 5 years (P = .27). The mean aortic valve area was 2.2+/-0.6 cm2 at 1 year and 2.3+/-0.7 cm2 at 5 years (P = .43). The mean left ventricular mass index (LVMI) was 104+/-31 g/m2 at 1 year and 97+/-24 g/m2 at 5 years (P = .08). Multivariate linear regression analysis showed that preoperative coronary artery disease (P<.0001) and hypertension (P<.01) were independent predictors of higher LVMI over time. Aortic insufficiency was none/trivial in 94% of patients and mild in 6% at 1 year. At 5 years, aortic insufficiency was none/trivial in 88% of patients, mild in 10%, and moderate in 2%. The aortic leaflets remained thin and pliable in all patients as assessed by echocardiography. Most patients (85%) were in New York Heart Association functional class I. The hemodynamic performance of the T-SPV remained unchanged during the first 5 years after implantation. The LVMI continued to decrease after the first year and tended to normalize in most patients. The aortic valve remained competent, and the leaflets did not change their thickness or show evidence of calcification.

Adult↗

PubMed1999

The Toronto SPV bioprosthesis: review of morphological findings in eight valves.

The morphological findings in eight explanted Toronto SPV bioprostheses were described. Clinical records were reviewed for patient information and data regarding the explanted bioprosthesis, all of which were analyzed in detail by gross and histological examination. All valves were also examined radiologically and detailed specimen photographs obtained. When warranted, tissue cultures were taken and special stains for microorganisms obtained. The Toronto SPV bioprosthesis has been used for aortic valve replacement in 270 patients since its introduction in 1991. The follow-up evaluation was 99.5% complete. Eight valves have been explanted: three at surgery and five at autopsy. Patient age ranged from 35 to 69 years, with five male and three female patients. Indications for aortic valve replacement were aortic stenosis in all cases. Implant duration ranged from 5 weeks to just over 6 years (mean 38 months). Early failures (2) were due to infective endocarditis. Two patients died of acute myocardial infarction, related to pre-existing coronary artery disease, and two died from lung cancer. All late explants showed host tissue growth (grade 2-3), with variable extension onto both the proximal and distal suture lines, as well as extension onto the cusps and commissures on the flow and nonflow surfaces. Extension of pannus onto native aortic tissues was seen but did not encroach on the coronary ostia. Tissue degenerative changes were present, as were small tears (type 1) in two valves. Mild calcification was seen in two valves. The Toronto SPV has excellent clinical performance at up to 8 years of follow-up evaluation. In this series, early failures are related to infective endocarditis, and later explants (6 of 8) are associated with mild tissue degeneration and an occasional cusp tear. At up to 5 years, only minimal/mild calcification was seen in two of the eight valves.

Adult↗

PubMed1998

Decreasing incidence of stroke during valvular surgery.

BACKGROUND: The predictors and causes of stroke after valvular surgery are incompletely defined. We examined the incidence, predictors, and mechanisms of stroke during valvular procedures over a 15-year time period. METHODS AND RESULTS: We retrospectively reviewed prospectively gathered data on 5954 consecutive patients undergoing valvular procedures at our institution from 1982 to 1996. Stroke was defined as persistent central nervous system deficit, usually with confirmatory CT imaging. Patients were divided into 3 groups according to date of operation: group 1, 1982 to 1986 (n = 1819); group 2, 1987 to 1991 (n = 2022); and group 3, 1992 to 1996 (n = 2113). Chart review was undertaken of all patients who developed stroke (n = 189). Stroke occurred in 3.8% of group 1 patients, 3.3% of group 2, and 2.6% of group 3 (P = 0.120). The decreasing incidence of stroke over time was confirmed by multivariable logistic regression analysis, in which earlier date of operation was an independent risk factor for stroke (P < 0.001). Predictors of stroke identified by multivariable logistic regression were (listed in decreasing order): (1) endocarditis (OR, 3.0; 95% CI, 1.8 to 5.0); (2) age > 74 years (OR, 2.3; 95% CI, 1.5 to 3.7); (3) earlier time period of operation (1982 to 1986: OR, 2.2; 95% CI, 1.5 to 3.2; 1987 to 1991: OR, 1.5; 95% CI, 1.0 to 2.2); (4) urgent timing (OR, 2.0; 95% CI, 1.4 to 2.8); (5) concomitant coronary bypass (OR, 2.0; 95% CI, 1.4 to 2.8); and (6) reoperation (OR, 1.7; 95% CI, 1.2 to 2.4). In more recent years of operation, we found an increasing prevalence of age > 74 years (7.4% in group 1, 9.5% in group 2, and 15.3% in group 3; P < 0.001), urgent timing (11%, 26%, and 34%, P < 0.001), and concomitant coronary bypass surgery (25%, 27%, and 33%; P < 0.001). CONCLUSIONS: The incidence of stroke during valvular surgery has decreased with time, despite an increased prevalence of risk factors. Predictors of stroke suggest 3 major causes (multivariable predictors in parentheses): atherosclerotic emboli (elderly age, concomitant coronary bypass), shock (urgent timing, reoperation), and septic emboli (endocarditis).

Aged↗

PubMed1998

Autopsies in acute type A aortic dissection. Surgical implications.

BACKGROUND: This study was undertaken to review autopsy findings in operative and nonoperative settings to define anatomic pathology, cause of death, and theoretical implications of operative and perfusion management strategies for acute Stanford type A dissection. METHODS AND RESULTS: Fifty autopsies for acute type A dissection performed between 1977 and 1995 were reviewed. Twenty-nine patients had no operative therapy (group A). Twenty-one patients received an operation (group B). Cause of death in the nonoperated group was tamponade or rupture in 23 patients (23 of 29, 79%). In the operated group, 1 patient died of rupture (1 of 21, 5%). The 2 most common causes of death in the operated group were major brain injury (7 of 21, 33%) and cardiac failure (7 of 21, 33%). Intimal disruption was present in 92% of patients (45 of 49). Twenty-four percent of these (12 of 49) had a secondary intimal injury site. Theoretic femoral arterial perfusion and application of an ascending aortic cross clamp would have left 42% of patients (21 of 50) at risk of false lumen perfusion against the aortic cross clamp. Replacement of the ascending aorta alone would have left residual arch intimal disruption in 32% of patients (16 of 50). Open arch inspection and repair when appropriate would have left a minimum number of patients with distal intimal disruption (8 of 50, 16%). CONCLUSIONS: Operative therapy successfully manages the primary cause of death in acute type A dissection. A theoretical repair that uses the open arch technique followed by antegrade perfusion eliminates or minimizes the risk of false lumen perfusion in the greatest number of patients. This technique may diminish neurological injury and distal anastomosis bleeding, thereby improving outcomes.

Acute Disease↗

PubMed1998

Fifteen-year trends in risk severity and operative mortality in elderly patients undergoing coronary artery bypass graft surgery.

BACKGROUND: Trends in risk-severity and operative mortality (OM) were examined in 3330 consecutive patients aged 70 years and older who underwent isolated coronary artery bypass graft surgery (CABG) between 1982 and 1996. METHODS AND RESULTS: The proportion of elderly patients rose significantly over time (P<.001). Crude OM among the elderly was 7.2% in 1982 to 1986, fell to 4.4% in 1987 to 1991, but did not improve thereafter. Logistic regression analysis of OM was used to construct relative risk groups (low, medium, or high). The prevalence of high-risk elderly patients rose significantly over time (P=.001) from 16.2% in 1982 to 1986 to 19.5% in 1987 to 1991 and 26.9% in 1992 to 1996. OM in high-risk patients fell significantly (P=.044) from 17.2% in 1982 to 1986 to 9.1% in 1987 to 1991 and was 8.9% in 1992 to 1996. Contemporary independent predictors of OM among elderly patients were poor ventricular function (LV grade 2 to 3, odds ratio [OR], 2.6; 95% confidence interval [CI], 1.3 to 5.2; and LV grade 4, OR, 10.7; 95% CI, 4.4 to 26); previous CABG (OR, 3.7; 95% CI, 2.0 to 7.0), female sex (OR, 1.8; 95% CI, 1.1 to 2.8), peripheral vascular disease (OR, 1.8; 95% CI, 1.1 to 2.8), and diabetes (OR, 1.7; 95% CI, 1.1 to 2.7). Previous angioplasty was protective (OR, 0.3; 95% CI, 0.1 to 0.9). CONCLUSIONS: OM in elderly patients has declined significantly in recent years despite an increase in the prevalence and severity of their risk factors. A careful weighing of risk, rather than advanced age alone, should determine who is offered surgical revascularization. In this regard, poor ventricular function and repeat CABG continue to have the greatest impact on OM in elderly patients.

Age Distribution↗

PubMed1998

Stentless aortic bioprostheses: compelling data from the Second International Symposium.

BACKGROUND: Stentless aortic xenografts are an important addition to the range of prosthetic valves. So far their use has been restricted to a limited number of study centers. This report summarizes the principal findings from the Second International Symposium on Stentless Bioprostheses. Attention is focused on the Toronto SPV and Freestyle valves recently approved by the United States Food and Drug Administration. METHODS: Stentless xenografts are used predominantly in elderly patients with aortic stenosis. Implant techniques are more complex than for stented valves, as reflected by longer ischemic and cardiopulmonary bypass times. The valves have been subjected to detailed serial echocardiographic assessment and clinical follow-up. RESULTS: The hemodynamic characteristics resemble those of the aortic homograft. There is a progressive increase in effective orifice area and decrease in transvalvular pressure gradients with time. Left ventricular mass index and wall thickness normalize between 6 and 12 months postoperatively. Left ventricular remodeling is accompanied by improved symptomatic status and a low incidence of valve-related complications. Limited comparative studies suggest important benefits over stented xenografts. Improved hemodynamics may translate into better bioprosthetic durability. CONCLUSIONS: Reproducible and reliable implant methods should be taught carefully, but the hemodynamic advantages are substantial. Stentless xenografts are ideal for the elderly patient with aortic stenosis.

Aorta↗

PubMed1998

Deep sternal wound infection: risk factors and outcomes.

BACKGROUND: Deep sternal wound infection (DSWI) is a serious complication of cardiac operations performed by median sternotomy. We attempted to define the predictors of DSWI and to describe the outcomes of two treatment strategies used at our institution. METHODS: Retrospective review was performed using prospectively gathered data on 12,267 consecutive cardiac surgical patients from 1990 to 1995. Chart review was performed on all patients in whom DSWI developed, and follow-up was obtained on 100% of these patients. RESULTS: Deep sternal wound infections developed in 92 patients (incidence 0.75%). Multivariable predictors for development of DSWI in all patients were (odds ratios and 95% confidence intervals in parentheses) (1) diabetes mellitus (2.6; 1.7 to 4.0) and (2) male sex (2.2; 1.3 to 3.9). In patients receiving coronary artery bypass grafting alone, independent predictors were (1) bilateral internal thoracic artery grafts (3.2; 1.1 to 8.9), (2) diabetes (2.7; 1.6 to 4.3), and (3) male sex (1.8; 0.9 to 3.7). For all other patients, predictors were (1) age more than 74 years (3.3; 1.1 to 10.1), (2) male sex (3.0; 1.1 to 8.1), and (3) diabetes (2.3; 0.9 to 5.8). Bilateral internal thoracic artery grafts increased the risk of DSWI in all subgroups of coronary artery bypass graft patients, particularly in diabetics who had a 14.3% incidence of DSWI after bilateral internal thoracic artery grafting. Patients with DSWIs received either sternal debridement with primary closure (n=45) or sternectomy with flap reconstruction (n=46). The 6-month freedom from adverse event rate (ie, readmission, reoperation, or death) was 76% for both groups of patients. CONCLUSIONS: Male sex and diabetes are predictors of DSWI in all cardiac surgical patients. Bilateral internal thoracic artery grafting may be contraindicated in diabetic patients.

Age Factors↗

PubMed1998

Circulatory arrest under moderate systemic hypothermia and cold retrograde cerebral perfusion.

BACKGROUND: Profound hypothermia is used for circulatory arrest during cardiovascular operations. Cold retrograde cerebral perfusion enhances cerebral protection during circulatory arrest. This study examines the results of circulatory arrest under moderate systemic hypothermia and cold retrograde cerebral perfusion. METHODS: Circulatory arrest under moderate systemic hypothermia (nasopharyngeal temperatures of 19 degrees to 28 degrees C, mean of 23 degrees C) and cold (10 degrees C) retrograde cerebral perfusion were employed in 104 consecutive patients for operation on the proximal aorta (103 patients) or for a venous tumor invading the heart (1 patient). Aortic operations consisted of replacement of the entire transverse arch in 49 patients, hemiarch in 16, ascending aorta in 37, and an extraanatomic aortic bypass in 1. Most patients (83%) also had other procedures such as coronary artery bypass or an aortic valve operation. Sixteen patients had had previous aortic operations. The mean circulatory arrest time was 27 minutes (range, 6 to 105 minutes). RESULTS: There were eight in-hospital deaths. Preoperative shock, peripheral vascular disease, and previous aortic operations were independent predictors of operative mortality. There were eight strokes; clinical assessment and computed tomographic scans of the brain suggested that the strokes were embolic in 6 patients. Atherosclerosis/laminated thrombi in the aorta and the duration of circulatory arrest were independent predictors of stroke. Four patients had seizures without neurologic deficit. No patient had development of paraplegia or paraparesis. CONCLUSIONS: Systemic hypothermia of 23 degrees C (nasopharyngeal) and cold retrograde cerebral perfusion (10 degrees C) appear to be safe for circulatory arrest times of less than 30 minutes. This strategy of cerebral protection may also be adequate for longer circulatory arrest times.

Brain↗

PubMed1998

The Hancock II bioprosthesis at 12 years.

BACKGROUND: The Hancock II bioprosthesis has been used for heart valve replacement since 1982 in our institution. We previously reported its clinical performance at 8 years and at 10 years. This is a progress report on its performance at 12 years. METHODS: From 1982 to 1994 the Hancock II bioprosthesis was used for aortic valve replacement (AVR) in 723 patients and for mitral valve replacement (MVR) in 328 patients. The mean age of the patients was 65 years for both groups. Coronary artery disease was present in 42% of patients who had AVR and 45% of patients who had MVR. Patients have been followed up prospectively at annual intervals; the mean follow-up was 68+/-40 months for AVR and 66+/-43 months for MVR; it was 99% complete. RESULTS: There were 36 (5%) operative and 159 late deaths in the AVR group, and 26 (8%) operative and 92 late deaths in the MVR. The actuarial survival at 12 years was 54%+/-4% for AVR and 42%+/-5% for MVR. Age greater than 65 years and coronary artery disease had a profound effect on late survival. At 12 years the freedom from thromboembolism was 86%+/-2% for AVR and 90% +/-2% for MVR; from endocarditis, 95%+/-1% for both groups; from primary tissue failure, 94%+/-2% for AVR and 82%+/-5% for MVR; and from valve reoperation, 89% +/-3% for AVR and 78%+/-5% for MVR. There was no primary tissue failure at 12 years in patients older than 65 years who had AVR. CONCLUSIONS: The clinical performance of the Hancock II has been very satisfactory and this bioprosthesis appears to be more durable than its predecessors.

Adolescent↗

PubMed1998

Aortic valve replacement with stentless and stented porcine valves: a case-match study.

OBJECTIVES: To assess the potential benefits of the hemodynamic superiority of stentless valves, we conducted a case-match study among patients who underwent aortic valve replacement with two types of porcine bioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis. METHODS: Preoperative clinical variables predictive of death after aortic valve replacement were determined by a stepwise logistic regression analysis in a series of 908 consecutive patients who received porcine aortic bioprostheses during a 14-year interval. Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independent predictors of death. On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the shortest interval for each matched pair, was 43 +/- 24 months for both groups. RESULTS: At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.006); the freedom from cardiac-related death was 95% +/- 4% for the Toronto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom from any valve-related complication was 81% +/- 5% for the Toronto SPV and 50% +/- 10% for the Hancock II (p = 0.008). A Cox proportional hazard model demonstrated a significant reduction in cardiac mortality rates and valve-related morbidity in patients who received the Toronto SPV bioprosthesis. CONCLUSIONS: Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-control study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.

Adult↗

PubMed1998

Long-term results of mitral valve repair for myxomatous disease with and without chordal replacement with expanded polytetrafluoroethylene sutures.

OBJECTIVE: This study was carried out to evaluate the long-term results of mitral valve repair for mitral regurgitation caused by myxomatous disease of the mitral valve and the late effects of chordal replacement with expanded polytetrafluoroethylene sutures in this operation. METHODS: A total of 324 patients with mitral regurgitation caused by myxomatous disease underwent mitral valve repair from 1981 to 1995; the group comprised 241 men and 83 women whose mean age was 58 +/- 14 years. Chordal replacement with expanded polytetrafluoroethylene sutures has been performed in 165 patients since 1985. Most of the patients who had chordal replacement with expanded polytetrafluoroethylene sutures had prolapse of the anterior leaflet or prolapse of both leaflets, whereas most patients who had mitral valve repair without chordal replacement had prolapse of the posterior leaflet. Patients were followed up at annual intervals and had a Doppler echocardiographic study. The follow-up was complete and extended from 6 to 156 months (mean 36 +/- 30 months). RESULTS: Two operative and 21 late deaths occurred (14 cardiac and 7 noncardiac). At 10 years the actuarial survival was 75% +/- 5%, the freedom from stroke was 94% +/- 2%, the freedom from transient ischemic attacks was 92% +/- 4%, the freedom from endocarditis was 99% +/- 1%, the freedom from mitral valve reoperation was 96% +/- 1%, and the freedom from severe mitral regurgitation was 93% +/- 3%. Chordal replacement with expanded polytetrafluoroethylene sutures had no effect on any of these end points. CONCLUSIONS: Mitral valve repair was feasible in most patients with mitral regurgitation caused by myxomatous disease and it was associated with low rates of valve-related complications. Chordal replacement with expanded polytetrafluoroethylene had no adverse effect on the late outcome and was believed to have increased the probability of mitral valve repair.

Adolescent↗

PubMed1998

Surgical repair of postinfarction ventricular septal defect by infarct exclusion.

Repair of postinfarction ventricular septal defect (VSD) by infarct exclusion has been used for a decade in our unit. It involves securing a glutaraldehyde-preserved bovine pericardial patch to the endocardium of the left ventricle all around the necrotic myocardium to exclude the VSD and the infarct from the left ventricular cavity. Fifty-two patients with postinfarction VSD underwent this type of repair from 1987 to 1996. Thirty-four patients were in shock when undergoing operation; 26 had anterior VSD and 26 had posterior. Ten patients died perioperatively, for surgical mortality of 19%. Three patients developed recurrent VSD; one died and two survived. Preoperative cardiogenic shock and age older than 70 years were associated with an increased operative mortality. Operative survivors were followed up from 6 to 135 months, mean of 65 months. The actuarial survival at 8 years was 59% +/- 6%. Repair of postinfarction VSD by infarct exclusion is a relatively simple operative procedure and seems to have improved the results of surgery in patients with posterior VSD.

Actuarial Analysis↗

PubMed1998

The use of pericardium in acquired heart disease: a review article.

Pericardium is an excellent material for reconstruction of the heart during the surgical management of certain acquired heart defects. This review details our experience with pericardium as a patch material for various parts of the left ventricle. MITRAL ANNULUS: Extensive calcification of the mitral annulus, abscess, multiple previous mitral valve replacements and rupture of the posterior wall of the left ventricle are challenging surgical problems that can be satisfactorily managed by reconstructing the mitral annulus with either fresh autologous or glutaraldehyde-fixed bovine pericardium. The mitral valve prosthesis is secured to the newly reconstructed mitral annulus. This procedure has proven to be durable and has provided very good long-term results. LEFT VENTRICULAR OUTFLOW TRACT: We have used bovine pericardium to enlarge the aortic annulus in patients with small aortic annulus undergoing aortic valve replacement with bioprosthetic valves. Patch enlargement of the aortic annulus probably increases the operative mortality of aortic valve replacement but it may favorably effect the clinical outcome and late survival. Another problem in the aortic root that frequently requires reconstruction with pericardium is aortic root abscess. We believe that radical resection of the abscess is the single most important component to eradicate infection in these patients. Pericardium is an excellent material to reconstruct all parts of the left ventricular outflow tract and the results have been excellent. RECONSTRUCTION OF THE LEFT VENTRICULAR WALL: We have also used pericardium to repair the left ventricle in patients with postinfarction ventricular septal defect. We have used a technique of infarct exclusion by suturing a properly tailored bovine pericardium to the endocardium of the left ventricle all around the infarct, excluding the left ventricular cavity from the infarcted wall. This technique has improved the outcome of surgery for this mechanical complication of myocardial infarction, particularly in patients with posterior interventricular septal rupture.

Aortic Valve↗

PubMed1998

Histological and morphometric analyses of early and late aortocoronary vein grafts and distal anastomoses.

BACKGROUND: Aortocoronary vein grafts develop fibromuscular intimal hyperplasia within the first year of implantation. Tissue remodeling may promote development of graft atherosclerosis and thrombosis. Angiographic studies show that human aortocoronary vein grafts in situ for one or more years become stenosed, preferentially at the distal anastomosis versus the body or trunk of the graft or at the proximal anastomosis. Previous studies have not reported morphological data on the nature and distribution of intimal lesions around the distal graft/artery anastomoses. OBJECTIVE: To examine and quantify histological and morphometric changes within the intima of 27 aortocoronary vein grafts and their distal anastomoses. METHODS: Seventy-two hearts obtained at autopsy and one at heart transplantation were examined, photographed and fixed in 10% buffered formaldehyde solution. Three to seven 3 mm long segments of grafts and their distal anastomoses were sectioned, stained and examined by light microscopy. RESULTS: Eleven early grafts were implanted for six weeks or less, and they showed significant cellular hyperplasia mainly at the suture line. In 16 late grafts in situ 1.5 to 15 years, the degree of fibromuscular intimal thickening was greatest on the hood and at the suture line, whereas on the floor of the native artery and in the graft body the degree of thickening was approximately one-third and two-thirds, respectively, that seen on the hood. CONCLUSIONS: Stenosis of aortocoronary vein grafts at their distal anastomosis is likely related to the preferential development of intimal thickening on the hood of the graft and at the suture line. Because fibromuscular intimal hyperplasia has been reported to play a role in the development of atherosclerosis and thrombosis in the body of vein grafts, this focal hyperplasia at the distal anastomosis may also play a role in vein graft failure.

Aged↗

PubMed1998

Aortic valve replacement with stentless porcine aortic valves: a ten-year experience.

BACKGROUND AND AIMS OF THE STUDY: It has been shown that although stentless porcine aortic valves have better hemodynamic features than stented porcine valves, their long-term durability remains unknown. This study was undertaken to examine the long-term clinical outcome of aortic valve replacement (AVR) with stentless porcine aortic valves. METHODS: Between 1987 and 1989, custom-made stentless valves were implanted in 29 patients (mean age 58 years), and between 1991 and 1997, the Toronto SPV was implanted in 213 patients (mean age 63 years). In addition to AVR, one-third of the patients had coronary artery bypass. All patients were followed up at annual intervals and underwent Doppler echocardiography. RESULTS: There were two operative and 11 late deaths (four cardiac, seven non-cardiac). The actuarial survival rate was 89 +/- 4% at nine years. There were two strokes and seven transient ischemic attacks; freedom from thromboembolic complications was 92 +/- 4% at nine years. Two patients developed infective endocarditis, one early and one late; freedom from prosthetic valve endocarditis was 98 +/- 1% at nine years. Freedom from primary tissue failure was 85 +/- 8% at nine years. Seven patients required repeat AVR, because of endocarditis (two) and aortic insufficiency (five); freedom from repeat AVR was 82 +/- 8% at nine years. Periodic hemodynamic assessment by echocardiography indicated that the mean systolic gradients across the valve decreased during the first year of implantation, the valve effective orifice increased, and valve competence remained stable. CONCLUSIONS: Stentless porcine aortic valves have provided excellent clinical results. These valves may suffer degenerative changes and fail at the same rate as stented porcine aortic valves but, because of their superior hemodynamic performance, they may enhance patients' survival by allowing complete regression of left ventricular hypertrophy and restoration of normal ventricular function.

Animals↗

PubMed1998

Twelve-year experience with Carpentier-Edwards PERIMOUNT pericardial valve in the mitral position: a multicenter study.

BACKGROUND AND AIMS OF THE STUDY: The study aim was to assess the durability of the Carpentier-Edwards PERIMOUNT pericardial bioprosthesis in the mitral position. METHODS: This seven-center retrospective clinical study involved the follow up of 333 patients who underwent isolated mitral valve replacement and 102 patients who underwent double (mitral and aortic) valve replacement with the PERIMOUNT pericardial valve between 1984 and 1989. Mean patient age at implant was 60.7 +/- 11.6 years; 41.1% were males. The most common etiology was rheumatic heart disease (53.9%) and the most common mechanism mitral insufficiency. All patients but six were followed for an average of 7.2 +/- 3.6 years after surgery; total follow up was 3071.7 patient-years (pt-yr). RESULTS: The total operative mortality rate was 7.6%; this included a valve-related mortality rate of 0.2%. The late mortality rate was 5.2% per pt-yr, of which 1.4% per pt-yr was considered valve-related. At 11 years, the overall actuarial survival rate was 53.3 +/- 2.8%, and actuarial freedom from valve-related death 83.9 +/- 2.6%. At follow up, 80% of patients were in NYHA class I or II, and 74% showed improvement. Twenty-eight incidences of deterioration requiring explant were observed. At 11 years the actuarial freedom from explant due to structural failure was 84.9 +/- 3.1%. Rates of structural failure decreased with age: the actuarial freedom from explant due to structural failure was 78.1 +/- 4.8% for patients aged < or = 60 years, 89.4 +/- 4.4% for those aged 61-70 years, and 100% for those aged over 71 years. CONCLUSION: The Carpentier-Edwards PERIMOUNT pericardial bioprosthesis is a reliable choice when a tissue valve is required, especially in patients over 60 years of age.

Bioprosthesis↗

PubMed1997

Aortic valve replacement with patch enlargement of the aortic annulus.

BACKGROUND: Aortic annulus enlargement has long been advocated for the placement of valve prostheses larger than otherwise would have been possible. Little information exists, however, on the short- and long-term outcome of this surgical procedure. METHODS: We performed a retrospective review of 530 patients enrolled in a registry for patients who underwent aortic valve replacement using the Hancock II bioprosthesis and were followed up prospectively over the course of 11 years at a single institution. In an effort to avoid prosthetic valve-patient mismatch, the aortic annulus was enlarged in 98 patients (18%). Short- and long-term outcome was analyzed. RESULTS: Enlargement of the aortic annulus during aortic valve replacement increased the operative mortality rate from 3.5% to 7.1%, but this difference did not reach statistical significance (p = 0.10). The long-term survival of patients who had annulus enlargement was similar to that of patients who did not. Because there were differences in the clinical profile of patients who had annulus enlargement and those who did not, a case-control study was carried out. This study showed similar long-term survival, freedom from valve-related and cardiac death, and combined end points in the two groups of patients. CONCLUSION: Aortic annulus enlargement increased the operative mortality of aortic valve replacement. However, patients who underwent enlargement of a small aortic annulus had long-term survival and freedom from cardiac and valve-related death comparable to those of patients who received larger aortic prostheses.

Aged↗