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Biomedical subjects

S B Colvin

Publications and source records attributed to S B Colvin.

At least 73 records · Page 4Linked to original sources
PubMed1994

Decreasing incidence of systolic anterior motion after mitral valve reconstruction.

BACKGROUND: With the widespread application of mitral valve reconstructive techniques, systolic anterior motion (SAM) of the anterior mitral leaflet causing left ventricular outflow tract obstruction has been recognized by several groups. SAM occurred in 9.1% of the first 441 patients operated on for mitral valve reconstruction at our institution. Fortunately, SAM subsided with medical therapy within 1 year for a majority of patients as reported in May 1993. Some surgeons, however, have considered abandoning repair for prosthetic replacement after SAM was detected on intraoperative echocardiogram. METHODS AND RESULTS: Since June 1991, a triangular anterior leaflet resection has been cautiously evaluated in patients with extensive anterior leaflet tissue. This has been performed in 23 of 119 patients. CONCLUSIONS: The frequency of SAM in the 119 study patients has decreased from 9.1% to 3.4%.

Female↗
PubMed1994

Effect of retrograde warm continuous cardioplegia on right ventricular function.

BACKGROUND: Although retrograde warm continuous cardioplegia (RWCC) has been recently advocated as a method of myocardial preservation during cardiac surgery, scant data exist on the effects of RWCC on right ventricular function. However, previous data have clearly shown that retrograde cardioplegia is poorly distributed to the right ventricle and interventricular septum. This experiment was performed to analyze functional preservation of the right ventricle after RWCC. METHODS AND RESULTS: Fourteen mongrel dogs were instrumented with sonomicrometers and pressure transducers to determine left and right ventricular (LV, RV) pressure-volume relationships and placed on cardiopulmonary bypass. All dogs underwent 90 minutes of aortic cross-clamping with either (1) RWCC (n = 7) after antegrade warm arrest or (2) retrograde cold multidose cardioplegia (RCMC) (n = 7) with topical hypothermia after antegrade cold arrest. All dogs received identical blood cardioplegia solutions. Ventricular function was measured before arrest and 30 and 60 minutes after unclamping. The end-diastolic-work area relationship was calculated, and the slope is presented as percent of baseline (mean +/- SEM; repeated measures ANOVA). At 30 minutes after unclamping, RWCC provided 68.77 +/- 9.09 for the left ventricle and 41.03 +/- 7.49 (P < .05 for RWCC versus RCMC for RV function at 30 minutes) for the right ventricle, and RCMC provided 62.80 +/- 7.23 for the left ventricle and 79.40 +/- 13.82 for the right ventricle. At 60 minutes after unclamping, RWCC provided 58.24 +/- 12.35 for the left ventricle and 48.05 +/- 9.72 for the right ventricle, and RCMC provided 65.38 +/- 6.76 for the left ventricle and 61.95 +/- 8.70 for the right ventricle. (P = NS for RWCC versus RCMC for LV function at either 30 or 60 minutes). These results demonstrate depressed recovery of RV function after 90 minutes of RWCC (P < .05 at 30 minutes after reperfusion) compared with RCMC. No difference in recovery of LV function was detected. CONCLUSION: RWCC may be harmful to the right ventricle and should be used with caution, particularly in patients with preexisting RV hypertrophy.

Animals↗
PubMed1993

Direct-current injury from external pacemaker results in tissue electrolysis.

In two patients undergoing open heart operations, electrochemical burns developed at the sites of connection to an external pacing system. Investigation revealed that failure of the pacing generator caused a small, continuous, direct current to pass through the patients, resulting in electrolysis at the sites of contact with the pacing and grounding wires. This electrolytic reaction was recreated in a mock pacing system and resulted in tissue injury and disintegration of the pacing wire. Guidelines to help recognize and prevent this complication are presented.

Aged↗
PubMed1993

Aortic aneurysm and dissection: normal MR imaging and CT findings after surgical repair with the continuous-suture graft-inclusion technique.

The normal range of postoperative imaging findings are described in 34 asymptomatic patients studied 5-66 months (mean, 28 months) after undergoing the continuous-suture graft-inclusion technique for repair of aortic aneurysms (n = 20) and dissections (n = 14) involving the ascending aorta. All 34 patients underwent magnetic resonance (MR) imaging, and 24 patients also underwent computed tomography (CT). Perigraft thickening was seen in 19 patients (56%) with MR imaging and in eight patients (33%) with CT. Flow outside the graft but contained within the native wrap was noted in five patients (15%) with MR imaging and in four patients (17%) with contrast material-enhanced CT. Thrombus was identified outside the graft and within the wrap in seven patients (21%) with MR imaging and in six patients (25%) with CT. Mass effect on the graft was depicted in four patients (12%) with MR imaging and in three patients (13%) with CT. Of the 14 patients who underwent repair of aortic dissections, an intimal flap was seen distal to the graft in seven of the 14 (50%) evaluated with MR imaging and in four of the 10 (40%) evaluated with contrast-enhanced CT. An accurate postoperative imaging evaluation requires precise knowledge of the surgical technique performed and its anatomic consequences.

Adolescent↗
PubMed1993

Role of amino acids and enhancement cardioplegia in routine myocardial protection. Experimental results.

The purpose of this study was to determine the effects of the addition of amino acids to blood cardioplegic solution and the value of terminal cardioplegia enhancement techniques in routine myocardial protection. Forty-five open-chest adult dogs were instrumented with sonomicrometry crystals to measure left ventricular long axis, midequatorial short axis, and wall thickness. The aorta was clamped for 120 minutes of cardiopulmonary bypass. Animals were randomly separated into four myocardial protection groups: (1) blood cardioplegic solution with amino acids and no terminal cardioplegia (n = 12); (2) blood cardioplegic solution with amino acids and warm amino acid terminal cardioplegia (n = 11); (3) blood cardioplegic solution with amino acids and cold amino acid terminal cardioplegia (n = 12); and (4) blood cardioplegic solution plus cold terminal cardioplegia (no amino acids, n = 10). Data for preload recruitable stroke work were obtained by inflow occlusion before bypass (baseline) and at 30 and 60 minutes after reperfusion and analyzed for changes in x-intercept and slope. A significant rightward shift in x-intercept did not occur in any group. When cardiac function was expressed as a percentage of baseline preload recruitable stroke work slope, improved functional recovery was seen at both 30 and 60 minutes in groups 2 (88.6% and 91.8%), 3 (85.8% and 86.9%), and 4 (88.6% and 92.6%) compared with group 1 (77.3% and 79.2%, p < 0.05). No significant difference was found in the degree of functional recovery among groups 2, 3, and 4. These results suggest that for myocardial protection of 2 hours in nonischemic hearts, a terminal dose of blood cardioplegic solution before unclamping is beneficial, but this positive effect is independent of amino acid supplementation and temperature.

Amino Acids↗
PubMed1993

Surgical repair of type A aortic dissection by the circulatory arrest-graft inclusion technique in sixty-six patients.

During an 8-year period (1984 to 1991) 66 patients (mean age 59 years, range 26 to 84 years) with type A aortic dissection (60 ascending aorta tears, 6 arch tears; 35 acute, 31 chronic) had surgical repair by a continuous suture-graft inclusion technique. Hypothermic circulatory arrest (16 degrees C) was used in 58 patients (35/35 acute, 23/31 chronic; mean arrest time 26 minutes, range 10 to 55 minutes). Fifty-two patients had hemiarch repair and 6 had total arch replacement. Aortic valve disease necessitated treatment in 38 patients (1 valved conduit, 20 valve replacements, 17 valve repairs). Recently 11 patients had valve repair by reconstruction of the native aortic root, by means of techniques similar to those used for homograft valve insertion. Operative mortality was 9% (14% acute, 3% chronic). Stroke occurred in 2 patients (3%) and was fatal in both. Variables suggestive of increased operative risk by univariate analysis were acuteness (p = 0.12), visceral ischemia (p = 0.12), and preoperative shock (p = 0.13). No variable was significant by multivariate analysis. Overall actuarial survival at 48 months was 77%, with 3 late deaths from a ruptured distal aneurysm. Late computed tomography or magnetic resonance imaging scan was done in 28 patients at a mean interval of 33 months. These studies identified 1 patient with a pseudoaneurysm requiring reoperation and 3 patients with contained flow between the graft and the wrap. Three patients required late operation: 1 for pseudoaneurysm, 1 for arch dissection, and 1 for repair of a distal aneurysm.

Actuarial Analysis↗
PubMed1992

Multiple valve operation for advanced valvular heart disease: results and risk factors in 513 patients.

To assess the results and incremental risk factors affecting outcome after multiple-valve operation in the early blood cardioplegia era of cardiac surgery, follow-up data (mean +/- SD 3.1 +/- 2 years) were obtained on 97% of 513 patients (mean age +/- SD 58.8 +/- 10.5 years) who underwent a multiple-valve procedure between June 1976 and August 1985. Preoperatively 41% of patients were in New York Heart Association functional class III and 54% in class IV. Three groups accounted for 98.6% of the patients: 57.7% had an aortic and mitral valve procedure, 29% had a mitral and tricuspid valve procedure and 11.9% had a triple-valve procedure. The overall hospital mortality rate was 12.5% and overall 5-year survival rate was 67.1%. Hazard function analysis for all deaths revealed systolic pulmonary artery pressure (p less than 0.0001), age (p = 0.005), triple valve procedure (p less than 0.005), concomitant coronary bypass operation (p less than 0.005) and prior cardiac surgery (p less than 0.002) as the significant incremental risk factors predicting decreased survival in the early hazard phase; diabetes (p less than 0.005) predicted decreased survival in the late hazard phase. Postoperatively the condition of 80% of the patients improved to functional class I or II; only 0.6% remained in functional class IV. The 5-year rate of freedom from late combined valve-related morbidity was 81.7% and that of freedom from late combined valve-related morbidity and mortality was 71.7%. These results demonstrate excellent clinical improvement and late survival after multiple valve operation in patients with advanced valvular heart disease, justifying aggressive surgical therapy in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioprosthesis↗
PubMed1992

The effects of different techniques of internal mammary artery harvesting on sternal blood flow.

We investigated chest wall blood flow in a canine model to determine if the technique used to harvest the mammary artery has a differential effect on residual chest wall blood flow. Eight dogs underwent bilateral internal mammary artery mobilization; one artery was harvested as a pedicle and the other was harvested as a skeletonized vessel. Residual blood flow to the chest wall distribution of each artery was measured with radioactive microspheres. Chest wall blood flow was significantly decreased from preharvest levels after internal mammary artery mobilization regardless of the technique used. Tissue blood flows decreased to 46.9%, 22.1%, and 41.2% of baseline values for the manubrium (p < 0.01), sternum (p < 0.001), and ribs (p < 0.05), respectively. Residual sternal blood flow on the side of the skeletonized vessel was significantly greater than on the side of the pedicle graft (2.60 +/- 0.68 versus 1.27 +/- 0.27 cm3/min/100 gm, p < 0.001). We conclude that minimization of tissue mobilization during internal mammary artery harvesting may reduce sternal devascularization. This finding may have clinical significance with respect to lowering the incidence of sternal wound complications in coronary bypass surgery using the internal mammary artery as a bypass conduit.

Animals↗
PubMed1992

Experience with twenty-eight cases of systolic anterior motion after mitral valve reconstruction by the Carpentier technique.

Systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction after Carpentier-type mitral reconstruction with ring annuloplasty has led some surgeons to abandon an otherwise successful repair or to avoid use of a rigid ring. To assess the long-term significance of such motion, we studied 439 patients undergoing Carpenter mitral reconstruction at our institution between March 1981 and June 1990. The hospital mortality rate was 4.8% (21/439) overall and 3.7% (9/243) for isolated mitral reconstruction. Systolic anterior motion was found in 6.4% (28/438) after the operation, and 2.3% (10/438) had a coexisting left ventricular outflow tract gradient (mean 53 mm Hg). Of the 28 patients with systolic anterior motion, 27 (96.4%) had leaflet prolapse, 17 (60.7%) had undergone more than a 3 cm resection of the posterior leaflet, and two (7.1%) had preexisting idiopathic hypertrophic subaortic stenosis. All patients were treated medically, 14 with negative inotropic agents. Follow-up echocardiograms at a mean of 32 months demonstrated the disappearance of systolic anterior motion in 13 of 28 patients (46.4%) and resolution of the outflow tract gradient in 10 of 10 (100%). At follow-up only one patient was in New York Heart Association class III or IV and required reoperation for rheumatic mitral insufficiency. These data demonstrate that systolic anterior motion after Carpentier mitral reconstruction with ring annuloplasty is not prevalent and should be managed medically in most cases. Associated left ventricular outflow tract obstruction resolves with medical treatment.

Cardiac Surgical Procedures↗
PubMed1991

Aortic valve replacement for aortic stenosis in persons aged 80 years and over.

Seventy-one patients aged greater than or equal to 80 years (mean +/- standard deviation 82 +/- 2) with aortic stenosis or mixed stenosis and regurgitation underwent aortic valve replacement alone (n = 35, group 1) or in combination with a coronary artery bypass procedure without any other valve procedure (n = 36, group 2). Preoperatively, 91% had severe cardiac limitations (New York Heart Association class III or IV). Hospital mortality was 12.7% overall (9 of 71), 5.7% (2 of 35) for group 1 and 19.4% (7 of 36) for group 2. Perioperatively, 1 patient (1.4%) had a stroke. Survival from late cardiac death at 1 and 3 years was 98.2 and 95.5%, respectively, for all patients, 100% for patients who underwent isolated aortic valve replacement, and 96.3 and 91.2%, respectively, for patients who underwent aortic valve replacement plus coronary artery bypass. Eighty-three percent of surviving patients had marked symptomatic improvement. Freedom from all valve-related complications (thromboembolism, anticoagulant, endocarditis, reoperation or prosthetic failure) was 93.3 and 80.4% at 1 and 3 years, respectively. Thus, short- and long-term morbidity and mortality after aortic valve replacement for aortic stenosis in patients aged greater than or equal to 80 years are encouragingly low, although the addition of coronary artery bypass grafting increases short- and long-term mortality.

Aged↗
PubMed1991

Successful modified Fontan procedure in an adolescent after left pneumonectomy.

We performed a Waterston's anastomosis on a patient with complicated tricuspid atresia when she was two months of age. At age 14 years she required left pneumonectomy for massive, idiopathic hemoptysis. Four months after the pneumonectomy we substituted a modified Fontan anastomosis for the Waterston anastomosis. Restudy when she was 17 years of age showed continued satisfactory function.

Adolescent↗
PubMed1991

Repair of posterior left ventricular aneurysm in a six-year-old boy.

Left ventricular aneurysms and diverticula are rarely encountered in the pediatric age group. This paper reports a case of congestive heart failure and mitral regurgitation in a 6-year-old boy with a large posterolateral left ventricular aneurysm. Complete repair was successfully performed by excision of the aneurysm and Dacron patch reconstruction of the left ventricular free wall. The patch extended onto the posterior annulus of the mitral valve, thus restoring the mitral valve to normal geometry and correcting the mitral insufficiency. The surgical literature on congenital cardiac diverticula and acquired aneurysms in children is reviewed and summarized.

Child↗
PubMed1991

Sternal wound infections and use of internal mammary artery grafts.

Previous studies have provided conflicting evidence as to whether an increased risk of mediastinitis is associated with use of the internal mammary artery as a coronary bypass graft. In this study the effects of internal mammary artery grafts on wound complications were analyzed in a prospective, nonrandomized fashion. At New York University Medical Center from January 1985 through May 1988, 2356 patients underwent isolated coronary revascularization. Among these patients 1394 received one or more internal mammary artery grafts (group I) and 962 had vein grafts only (group II). Group I had a mean age of 59.5 years versus 67.7 years in group II; diabetes was equally present in both groups (22.7% versus 24.7%). Operative mortality rate was 1.3% in group I and 5.6% in group II. Sternal infection was significantly more prevalent in group I (2.2%, 31/1394) than in group II (0.8%, 8/962). Multivariate analysis revealed that aortic crossclamp time, use of a single internal mammary artery graft, use of a double mammary graft, and diabetes were associated with increased risk of sternal infection. The use of bilateral internal mammary artery grafting doubled the odds ratio of the risk compared with use of a single mammary graft, and the combination of diabetes and double internal mammary artery grafts increased the odds ratio 13.9-fold. Patients with an internal mammary artery graft who had sternal infection had a longer period of hospitalization than patients without a mammary artery graft who had sternal infection. We conclude that the risk of sternal infection is increased by the use of an internal mammary artery graft, especially use of double mammary grafts in the presence of diabetes.

Aged↗
PubMed1991

Biventricular distribution of cold blood cardioplegic solution administered by different retrograde techniques.

Although retrograde cardioplegia has been shown to provide adequate overall protection to the myocardium, delivery of cardioplegic solution to the right ventricle and septum is poor. We used an animal model of occlusion of the left anterior descending coronary artery to study the effects of modifying the conditions of retrograde cardioplegia administration on delivery to the right and left ventricles. Adult mongrel dogs (n = 12) were each given five retrograde injections of microsphere-labeled cardioplegic solution at 10-minute intervals. Four injections were made directly into the coronary sinus with ostial balloon occlusion at the following dosages and pressures: (1) 10 ml/kg at 30 mm Hg, (2) 20 ml/kg at 30 mm Hg, (3) 10 ml/kg at 50 mmHg, and (4) 20 ml/kg at 50 mm Hg. A fifth dose (20 ml/kg) was given directly into the right atrium at 50 mm Hg. Delivery of cardioplegic solution to the left and right ventricles was significantly reduced when the right atrial route was compared with the coronary sinus route at the same dosage and pressure (for left ventricle, 6.0% +/- 1.4% versus 22.7% +/- 11.4%/100 gm, p less than 0.001; for right ventricle, 0.7% +/- 0.2% versus 4.1% +/- 0.4%/100 gm, p less than 0.001). Septal delivery was less than that to the anterior and posterior left ventricle (10.4% +/- 1.3% versus 30.3% +/- 3.9% and 27.9% +/- 3.1%/100 gm, p less than 0.0001) for all injections. Delivery to the body of the right ventricle was less than that to the inflow and outflow tracts (1.8% +/- 0.2% versus 4.5% +/- 0.7% and 8.4% +/- 1.5%/100 gm, p less than 0.0001). These results indicate that, in this model, (1) the right atrial route provides less overall cardioplegic solution to both ventricles than direct retrograde coronary sinus cardioplegia and (2) regional abnormalities in distribution with direct retrograde coronary sinus cardioplegia are not affected by changes in the dosage or pressure of injection.

Animals↗
PubMed1990

Ten-year experience with aortic valve replacement in 482 patients 70 years of age or older: operative risk and long-term results.

A retrospective analysis of an institutional experience with aortic valve replacement (AVR) in patients 70 years of age or older during 1976 to 1987 was performed. The study was prompted in part by the current interest in palliative aortic valvoplasty, an interest based to a certain extent on the impression that AVR in the elderly has a high mortality. The mean age of the patients was 75.0 +/- 4.0 years (+/- the standard deviation) (range, 70 to 89 years). Eighty-three percent of patients received porcine valves and 17%, mechanical valves. Preoperatively 32% were in New York Heart Association class III, and 59% were in class IV. Operative mortality was 5.6% for elective isolated AVR for aortic stenosis (19% of all patients), 8.2% for all isolated AVR (38%), and 12.4% overall. Concomitant operative procedures were done in 62.0%; AVR with coronary artery bypass grafting (42%) had an operative mortality of 14.3%. Multivariate analysis showed significant predictors of operative mortality to be emergency operation (p less than 0.01), isolated aortic regurgitation (p = 0.01), and previous cardiac operation (p = 0.02). Follow-up (34 +/- 27 months) was 94% complete. Five-year survival from late cardiac-related death was 81.0%. The constant yearly hazard rate for late death for patients 70 years of age or older who underwent AVR was 5.42% per year, which is similar to the 5.77% per year rate calculated for age-matched and sex-matched controls. Five-year freedom from reoperation was 99%; from late thromboembolic complications, 91%; and from late anticoagulant-related complications, 94%. Freedom from all valve-related morbidity and mortality was 61% at 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1989

A comparison of mitral valve reconstruction with mitral valve replacement: intermediate-term results.

The continued good results after mitral valve reconstruction prompted this retrospective study to compare operative and late results from our institutional experience since 1976 with 975 porcine mitral valve replacements (MVRs) (1976 to December 1987), 169 mechanical MVRs (1976 to December 1987), and 280 Carpentier-type mitral valve reconstructions (CVRs) (1980 to mid-1988). The operative mortality was 2.0% for isolated CVR, 6.6% for isolated mechanical MVR, and 8.5% for isolated porcine MVR. The overall operative mortality was 5.0% for CVR, 16.6% for mechanical MVR, and 10.6% for porcine MVR. The overall 5-year survival including hospital deaths was 76% for CVR, 72% for mechanical MVR, and 69% for porcine MVR. By multivariate analysis, the predictors of increased operative risk and of decreased survival were age, New York Heart Association functional class IV status, previous cardiac operation, and performance of concomitant cardiac surgical procedures. The type of valvular procedure was not predictive of operative risk or overall survival. The 5-year freedom from reoperation was 94.4% for nonrheumatic patients having CVR, 77.4% for rheumatic patients having CVR, 96.4% for mechanical MVR, and 96.6% for porcine MVR (p less than 0.05, rheumatic patients with CVR versus both MVR groups). The 5-year freedom from all valve-related morbidity and mortality was significantly better for valve reconstruction compared with both types of valve replacement. Thus, the operative risk and late survival obtained after mitral valve reconstruction were at least equivalent to those obtained after MVR. In addition, patients receiving mitral valve reconstruction had less valve-related combined morbidity than patients receiving valve replacement, thus making mitral valve reconstruction preferable in some patients with mitral insufficiency.

Adolescent↗
PubMed1989

Ten-year operative experience with 165 aneurysms of the ascending aorta and aortic arch.

Results of surgery in 165 patients with aneurysms of the ascending aorta and aortic arch during 1978-1988 were analyzed retrospectively. Etiology included 29% dissection, 22% atherosclerosis, 22% cystic-medial necrosis, and 27% other causes. Concomitant procedures on the aortic valve were performed in 65% of patients (valvular replacement in 37%, valve-conduit in 23%, and valvular resuspension in 5%), and 13% underwent concomitant coronary artery bypass surgery. Major changes in our operative technique for such aneurysms have been introduced during the last 5 years, especially use of a continuous suture-graft-inclusion technique in 99% of patients, use of circulatory arrest in 59%, and use of an open hemiarch repair in 32%. Hospital mortality dropped from 17.9% during the first 5 years of the study period to 12.3% in the last 5 years despite increasing complexity of the cases encountered. Operative mortality was 7.6% for ascending aortic aneurysmal repair; 5.3% for valve-conduit procedure; 8.8% for open hemiarch repair; and 30.8% for repair of extensive aneurysms involving the aortic arch and significant portions of the descending aorta. Multivariate analysis showed that, of the variables examined, significant predictors of increased operative risk were age (p less than 0.05) and extension of an ascending aortic aneurysm to the descending aorta or involvement of the aortic arch (p less than 0.001). The incidence of stroke was 2.4%, with only one stroke since 1983 despite more extensive use of circulatory arrest since that time. Follow-up was 94% complete, with a mean (+/- SD) follow-up interval of 28 +/- 24 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗