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Biomedical subjects

F C Spencer

Publications and source records attributed to F C Spencer.

At least 37 records · Page 2Linked 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

Differences in carotid shunt flow rates and implications for cerebral blood flow.

A wide variety of carotid shunts are available for use in extracranial carotid surgery. Since it is commonly assumed that when properly positioned all shunts are equal in ability to protect the brain from cerebral ischemia, the choice of shunt is usually based on handling characteristics. However, after an intraoperative stroke occurred in a patient, we compared shunt flow rates using a simple and reproducible method of measurement. A mock circuit was created using a saline-filled fluid reservoir connected to the particular shunt being tested via 1/2-inch tubing. Hydrostatic pressure across the shunt was varied by changing the height of the reservoir, and the flow was collected over 30-second intervals. Multiple flow rate measurements were performed for each shunt with pressure gradients varying from 25 to 150 cm H2O. The data show significant hemodynamic differences among commercially available carotid shunts. A pressure gradient of 75 cm H2O produced a 2.8-fold variation in the amount of fluid delivered by various shunts. Minimal cerebral blood flow requirements and the possibility of underperfusion require that the surgeon consider such data in choosing an appropriate carotid shunt.

Blood Flow Velocity↗
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↗
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

Treatment of AIDS-related bronchopleural fistula by pleurectomy.

Spontaneous pneumothorax in patients with acquired immunodeficiency syndrome (AIDS) may require prolonged therapy for treatment of a persistent bronchopleural fistula, and treatment by standard methods often fails. This pilot study was done to test the effectiveness of aggressive surgical therapy for definitive treatment of persistent bronchopleural fistula in patients with AIDS. Between March 1989 and September 1991, 44 patients with AIDS were treated for spontaneous pneumothorax with closed tube thoracostomy; 14 of these patients had development of persistent bronchopleural fistula for more than 10 days, and 2 patients had subsequent bronchopleural fistula on the opposite side. Operative therapy in 14 patients included 15 thoracotomies and one sternotomy. The bronchopleural fistula was closed directly with suture or staples in 15 procedures and resected by lobectomy in 1 patient. All 14 patients received adjuvant parietal pleurectomy. Operative mortality was 7% (1 of 14 patients). The fistula was closed in all survivors and 13 patients were discharged between 7 and 28 days postoperatively. Pathologic examination confirmed Pneumocystis carinii in 13 patients with a high incidence of diffuse involvement and subpleural necrosis, further demonstrating the need for pleurectomy. These data suggest that in selected patients bronchopleural fistulas associated with AIDS can be effectively controlled by surgical closure combined with pleurectomy.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Surgical implications of transesophageal echocardiography to grade the atheromatous aortic arch.

Stroke is an especially serious complication of cardiopulmonary bypass with an incidence of 2% to 5%. This prospective study used transesophageal echocardiography (TEE) in 97 patients more than 65 years of age (mean age, 73 years) to identify those at high risk for aortic atheroemboli. The atheromatous disease of the aorta was graded by TEE: grade I = minimal intimal thickening (n = 29); II = extensive intimal thickening (n = 33); III = sessile atheroma (n = 15); IV = protruding atheroma (n = 10); V = mobile atheroma (n = 10). Clinical evaluation was also performed by intraoperative aortic palpation. Four patients who were graded as having normal aortas by palpation had intraoperative strokes. In contrast, 3 of these 4 patients were in grade V on TEE. The relationship of TEE to incidence of stroke was statistically significant (p less than 0.006), whereas there was no significant correlation between clinical grade and stroke incidence. Four of 10 TEE grade V patients were treated with hypothermic circulatory arrest and aortic arch debridement, and none suffered strokes. The other 6 patients were treated with standard techniques, and 3 had strokes. These results suggest that patients with mobile atheromatous disease are at high risk for embolic strokes that are not predicted by routine clinical evaluation. Selective use of circulatory arrest in the presence of TEE-detected mobile arch atheromas may reduce the risk of intraoperative stroke.

Aged↗
PubMed1992

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography.

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.

Aged↗
PubMed1992

Significant trends in the treatment of hepatic trauma. Experience with 411 injuries.

Several significant advances in the treatment of hepatic injuries have evolved over the past decade. These trends have been incorporated into the overall treatment strategy of hepatic injuries and are reflected in experiences with 411 consecutive patients. Two hundred fifty-eight patients (63%) with minor injuries (grades I to II) were treated by simple suture or hemostatic agents with a mortality rate of 6%. One hundred twenty-eight patients (31%) sustained complex hepatic injuries (grades III to V). One hundred seven patients (83.5%) with grades III or IV injury underwent portal triad occlusion and finger fracture of hepatic parenchyma alone. Seventy-three surviving patients (73%) required portal triad occlusion, with ischemia times varying from 10 to 75 minutes (mean, 30 minutes). The mortality rate in this group was 6.5% (seven patients) and was accompanied by a morbidity rate of 15%. Fourteen patients (11%) with grade V injury (retrohepatic cava or hepatic veins) were managed by prolonged protal triad occlusion (mean cross-clamp time, 46 minutes) and extensive finger fracture to the site of injury. In four of these patients an atrial caval shunt was additionally used. Two of these patients survived, whereas six of the 10 patients managed without a shunt survived, for an overall mortality rate of 43%. Over the past 4 years, six patients (4.7%) with ongoing coagulopathies were managed by packing and planned re-exploration, with four patients (67%) surviving and one (25%) developing an intra-abdominal abscess. One additional patient (0.8%) was managed by resectional debridement alone and survived. During the past 5 years, 25 hemodynamically stable and alert adult patients (6%) sustaining blunt trauma were evaluated by computed tomography scan and found to have grade I to III injuries. All were managed nonoperatively with uniform success. The combination of portal triad occlusion (up to 75 minutes), finger fracture technique, and the use of a viable omental pack is a safe, reliable, and effective method of managing complex hepatic injuries (grade III to IV). Juxtahepatic venous injuries continue to carry a prohibitive mortality rate, but nonshunting approaches seem to result in the lowest cumulative mortality rate. Packing and planned reexploration has a definitive life-saving role when used adjunctively in the presence of a coagulopathy. Nonoperative management of select hemodynamically stable adult patients, identified by serial computed tomography scans after sustaining blunt trauma is highly successful (95-97%).

Adult↗
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

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↗
PubMed1990

Experience with selective operative and nonoperative treatment of splenic injuries in 193 patients.

During the past decade splenic salvage procedures rather than splenectomy have been considered the preferred treatment for traumatic splenic injuries. Splenic preservation has been most often accomplished by splenorrhaphy and more recently by a controversial nonoperative approach. This report delineates indications, contraindications, and results with splenectomy, splenorrhaphy, and nonoperative treatment based on an 11-year experience (1978 to 1989) in which 193 consecutive adult patients with splenic injuries were treated. One hundred sixty-seven patients (86.5%) underwent urgent operation. Of these, 111 (66%) were treated by splenorrhaphy or partial splenectomy and 56 (34%) were treated by splenectomy. During the last 4 years, 26 additional patients (13.5%) were managed without operation. Patients considered for nonoperative treatment were alert, hemodynamically stable with computed tomographic evidence of isolated grades I to III splenic injuries. Overall 24% of the injuries resulted from penetrating trauma, whereas 76% of the patients sustained blunt injuries. Complications were rare, with two patients in the splenorrhaphy group experiencing re-bleeding (1.8%) and one patient (4%) failing nonoperative treatment. The mortality rate for the entire group was 4%. This report documents that splenorrhaphy can safely be performed in 65% to 75% of splenic injuries. Splenectomy is indicated for more extensive injuries or when patients are hemodynamically unstable in the presence of life-threatening injuries. Nonoperative therapy can be accomplished safely in a small select group (15% to 20%), with a success rate of nearly 90% if strict criteria for selection are met.

Adult↗