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Biomedical subjects

V L Gott

Publications and source records attributed to V L Gott.

At least 19 recordsLinked to original sources

Aortic root replacement. Risk factor analysis of a seventeen-year experience with 270 patients.

Between September 1976 and September 1993, 270 patients underwent aortic root replacement at our institution. Two hundred fifty-two patients underwent a Bentall composite graft repair and 18 patients received a cryopreserved homograft aortic root. One hundred eighty-seven patients had a Marfan aneurysm of the ascending aorta (41 with dissection) and 53 patients had an aneurysm resulting from nonspecific medial degeneration (17 with dissection). These 240 patients were considered to have annuloaortic ectasia. Thirty patients were operated on for miscellaneous lesions of the aortic root. Thirty-day mortality for the overall series of 270 patients was 4.8% (13/270). There was no 30-day mortality among 182 patients undergoing elective root replacement for annuloaortic ectasia without dissection. Thirty-six of the 270 patients having root replacement also had mitral valve operations. There was no hospital mortality for aortic root replacement in these 36 patients, but there were seven late deaths. Twenty-two patients received a cryopreserved homograft aortic root; 18 of these were primary root replacements and four were repeat root replacements for late endocarditis. One early death and two late deaths occurred in this group. Actuarial survival for the overall group of 270 patients was 73% at 10 years. In a multivariate analysis, only poor New Year Heart Association class (III and IV), non-Marfan status, preoperative dissection, and male gender emerged as significant predictors of early or late death. Endocarditis was the most common late complication (14 of 256 hospital survivors) and was optimally treated by root replacement with a cryopreserved aortic homograft. Late problems with the part of the aorta not operated on occur with moderate frequency; careful follow-up of the distal aorta is critical to long-term survival.

Actuarial Analysis

Composite graft repair of Marfan aneurysm of the ascending aorta: results in 150 patients.

One hundred fifty consecutive Marfan patients undergoing composite graft repair of an ascending aorta aneurysm are reported. Twenty-six of the 150 patients had a preoperative dissection of the ascending aorta. There were no early deaths among 138 patients undergoing elective composite graft repair. There was one early death among 12 patients undergoing urgent operation; this patient arrived at the hospital with a rupturing aneurysm. Twenty-four of the 150 patients had mitral procedures; there were no early deaths in this group. There have been 14 late deaths among the 149 hospital survivors (9%). Actuarial survival of 150 patients at 1, 5, 10, and 14 years was 93%, 92%, 81%, and 73% respectively. Risk factors for early or late death were identified by multivariate analysis and only New York Heart Association class (III or IV) and male gender emerged as significant independent predictors of mortality. Late complications directly related to the composite graft have been gratifyingly low; only 2 patients had coronary dehiscence and 3 had thromboembolic events. Endocarditis emerged as an important late complication in 8 patients (5%). Two patients were successfully treated with antibiotics, 3 died before widespread availability of cryopreserved homografts, and 3 patients treated with antibiotics and homograft root replacement have had no evidence of recurrent infection. Seven patients with dissection in this series had aortic diameters of 6.5 cm or less. This experience supports the concept that composite graft repair in Marfan patients is mandated when the aneurysm reaches 5.5 to 6 cm, even in the asymptomatic patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis

Current indications, risks, and outcome after pericardiectomy.

A retrospective analysis of the records of 60 patients who underwent pericardiectomy over a 10-year period (1980 to 1990) at The Johns Hopkins Hospital was performed. Indications for operation were effusive disease in 24 patients and constriction in 36 patients. Six patients (10%) with pericardial effusion had pain as the primary symptom necessitating intervention. The operative approach for pericardiectomy was median sternotomy in 52 patients (4 patients required cardiopulmonary bypass) and left anterior thoracotomy in 8 patients. Nine patients (5 with constriction and 4 with effusion) with a prior limited pericardial procedure required formal pericardiectomy. The operative mortality rate for pericardial effusion and constriction was 4.2% and 5.6%, respectively. Follow-up (median follow-up, 56.9 +/- 38.2 months) was obtained on 56 patients (93.3%). Actuarial survival at 1 year, 5 years, and 10 years for all patients was 82.1% +/- 5.1%, 71.7% +/- 6.7%, and 59.8% +/- 12.2%, respectively. A Cox proportional hazards regression analysis was performed using 20 clinical variables. A history of malignancy, previous pericardial procedure, and preoperative New York Heart Association class IV were found to be predictors of poor survival. All patients who underwent operation primarily for effusion with associated pain are alive and have improved functional capacity without steroid use. We conclude that pericardiectomy can be performed with low mortality and can result in good long-term survival and improved functional capacity. Patients who are seen primarily with pain refractory to steroid therapy can be relieved of symptoms with operation.

Actuarial Analysis

Composite graft repair of Marfan aneurysm of the ascending aorta: results in 100 patients.

One hundred consecutive patients with the Marfan syndrome underwent composite graft repair of an ascending aortic aneurysm between September 1976 and June 1989. Twenty-two patients had ascending aortic dissection at the time of composite graft repair; 18 patients also had a mitral valve procedure. There were no hospital deaths among 92 patients undergoing elective repair. One of 8 patients undergoing emergency repair of a ruptured aneurysm died in the operating room. The overall hospital mortality rate was 1%. There have been ten late deaths among the 99 hospital survivors (10.1%). Five deaths occurred among the first 11 patients in this series and five occurred among the last 88 patients (5.7%). Three late deaths resulted from composite graft endocarditis; 3 other patients with endocarditis are alive after aortic root replacement with cryopreserved homografts. Late coronary dehiscence caused death in 1 patient and was successfully repaired in a second. Actuarial survival for the 100 patients was 92.6% at 5 years and 75.8% at 10 years. Currently, composite graft repair of Marfan aneurysms of the ascending aorta can be performed with low hospital and late mortality. Marfan aneurysms with a diameter of 6 cm or greater should be repaired with the Bentall composite graft procedure, even if the patient is asymptomatic.

Adolescent

Routine use of the left internal mammary artery graft in the elderly.

Left internal mammary artery (LIMA) grafts have better long-term patency rates than do saphenous vein grafts and result in improved late survival. The present study was undertaken to assess the results of LIMA grafting in the elderly. From 1980 through 1988, 723 patients 70 years of age or older had isolated coronary artery bypass grafting performed. During the first 5 years, only 11% of the elderly patients received LIMA grafts, whereas 86% having coronary artery bypass grafting since 1985 had LIMA grafts. Since 1986, LIMA use in the elderly has become routine, with 92% of patients receiving internal mammary artery grafts. During the first 5 years, elderly patients had a hospital mortality rate of 9.3%. Since 1985, the hospital mortality rate fell to 5.5%. In addition, the occurrence of major surgical complications was either unchanged or reduced in patients receiving LIMA grafts. Furthermore, late follow-up indicates a significantly improved 4-year survival rate in patients with internal mammary artery grafts compared with those without: 86 +/- 0.02% versus 77 +/- 0.03% (p less than 0.01). Analysis of multiple potential risk factors for early mortality was performed using multiple logistic regression and late survival using the Cox proportional hazards model. Although unmeasured predictor variables may confound retrospective analyses, LIMA grafting appears to be an independent predictor both of improved early and late survival.

Aged

C. Walton Lillehei and total correction of tetralogy of Fallot.

In March 1954, an operating team headed by C. Walton Lillehei introduced the technique of cross circulation for the first-ever total corrections of ventricular septal defect, tetralogy of Fallot, and atrioventricular canal. Ten of 45 patients operated on with this technique of cardiopulmonary bypass had correction of tetralogy of Fallot, and the results with these 10 patients were reported in a landmark article. The operative results achieved in 1954 and 1955 by Lillehei and his team using cross circulation were truly remarkable. In addition, the University of Minnesota team concomitantly developed a host of new techniques and biomedical devices that made subsequent cardiac operative procedures safer and simpler to perform. These techniques and devices included the first ventricular septal defect prosthetic patch, the first right ventricular outflow patch, the first clinically applicable bubble oxygenator, and the first intramyocardial electrode used in combination with an external pacemaker for a patient with complete heart block.

Cardiac Surgical Procedures

Long-term results of total repair of tetralogy of Fallot in childhood.

Between 1958 and 1977, 170 children aged 10 years or less underwent total repair of tetralogy of Fallot at The Johns Hopkins Hospital. Follow-up data were obtained on 128 (90%) of the 143 who survived the operation at 10 to 28 years postoperatively (mean follow-up, 18 years). All patients completed an extensive questionnaire, and 59 returned for a thorough evaluation consisting of a history and physical examination, electrocardiogram, 24-hour Holter monitoring, exercise stress testing, pulmonary function testing, and two-dimensional and Doppler echocardiography. Late survival was excellent with only two of four known late deaths due to cardiac-related causes and with all 59 patients in New York Heart Association class I or II. None had cyanosis or clubbing. Normal sinus rhythm was present in 90%. One patient had complete heart block, and 75% had right bundle-branch block on the electrocardiogram. Right ventricular function was normal by echocardiography in 78%. Residual mild to moderate pulmonary stenosis was noted by Doppler study in 8 patients. Pulmonary regurgitation was present in 78%, but in only 11 patients was it graded as moderate and in none was it severe. Stress testing documented the excellent functional status of most patients, with 92% of predicted exercise time and 94% of maximum heart rate being attained. In the few who had impaired cardiac performance, this correlated best with moderate pulmonary regurgitation. Although the overall late functional status of patients undergoing repair in the first decade of life was very good, these patients need continued follow-up to assess the severity of pulmonary regurgitation and the need of possible intervention.

Adult

Development of a carbon-coated, central-hinging, bileaflet valve.

Between April 1963 and January 1966, 86 patients at the University of Wisconsin Hospital underwent aortic or mitral valve replacement, or both, with a carbon-coated, central-hinging, bileaflet valve. A 25-year follow-up has been obtained on 43 of these patients discharged with an aortic prosthesis, 13 patients discharged with a mitral prosthesis, and 2 patients discharged with double prostheses. The mean implantation time was 7.2 years, 9.0 years, and 9.5 years, respectively. The longest aortic valve implantation time was 24.2 years in a patient who had her bileaflet valve prophylactically replaced, and the longest mitral implantation time is 24 years in a patient who is doing well with her original prosthesis. We are not aware of any patient among the approximately 700 receiving this valve around the world who has developed fatigue-failure of the silicone-impregnated Teflon fabric leaflet. This valve has demonstrated unexpected durability and has provided some design and biomaterial concepts that are used in a number of current prosthetic valves.

Aortic Valve

C. Walton Lillehei and his trainees: one man's legacy to cardiothoracic surgery.

Between 1951 and 1967, Dr. C. Walton Lillehei trained 134 cardiothoracic surgeons at the University of Minnesota Hospital. Between 1967 and 1979, he trained another 20 surgeons at the New York Hospital-Cornell Medical Center. Twenty-three of these 154 Lillehei trainees became program directors of cardiothoracic programs and in turn trained 477 additional surgeons. Twenty-one of these second-generation trainees became program directors and trained 164 surgeons. Two of these third-generation trainees have become directors and have in turn trained 25 additional trainees. A total of at least 820 cardiothoracic surgeons, currently residing in 36 countries, can trace their preceptor lineage back to Dr. Lillehei. A number of significant clinical and research contributions have been forthcoming from these Lillehei trainees during the past 35 years.

Cardiac Surgical Procedures

Systolic expansion of the aortic root: an echocardiographic and angiographic sign of aortic composite graft dehiscence.

Precise diagnosis of aortic composite graft dehiscence may be difficult. We present a case illustrating this problem and its resolution. Two-dimensional echocardiography and contrast ventriculography revealed a space adjacent to the aortic valve conduit that demonstrated marked systolic expansion. The dynamic variation of this space was secondary to communication with the left ventricular cavity caused by disruption of the composite graft valve ring. Thus, systolic expansion of the aortic root is a useful echocardiographic and angiographic sign of composite graft dehiscence.

Adult

Reducing intraoperative myocardial acidosis by continuous cardioplegic perfusion via the coronary sinus.

Continuous retrograde coronary sinus perfusion (RCSP) can deliver cardioplegic solution homogeneously to the myocardium via the disease-free venous system. However, administration of cardioplegic solution through the coronary venous system necessitates low pressure infusion which may limit the rate of cardioplegic delivery. In addition, infusion of the solution at low flow rates may not prevent the development of myocardial acidosis during arrest. To determine if RCSP is capable of limiting intraoperative myocardial acidosis, open-chest pigs, monitored by intramyocardial pH probes, underwent cardioplegic arrest with a single dose aortic root infusion followed by a 45-min period of no RCSP (Group 1), RCSP of 25 mEq/liter bicarbonate-buffered cardioplegic solution (Group 2), RCSP of blood-buffered cardioplegic solution (Group 3), and RCSP of histidine-buffered cardioplegic solution (Group 4). There were no significant differences between the groups with respect to baseline pH, with a range of 7.27 to 7.32. At the end of the 45-min arrest period, Group 2 had a statistically higher pH, 7.06 +/- 0.08, compared to Group 1, 6.74 +/- 0.08 (P less than 0.05). Hearts in Groups 3 and 4 demonstrated preservation of preischemic pH levels after 45 min of arrest, 7.29 +/- 0.07 and 7.37 +/- 0.10, respectively, significantly higher than either Group 1 or 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis

Aortic valve selection in the elderly patient.

To determine the influence of valve selection on valve-related morbidity and mortality and patient survival, comparative long-term performance characteristics of mechanical (N = 68) and bioprosthetic (N = 73) heart valves were analyzed for 141 patients more than 70 years old who underwent isolated aortic valve replacement between 1970 and 1985. Cumulative patient follow-up was 491 patient-years (average, 4.3 years per patient). Hospital mortality was 18% and 19% for patients with mechanical valves and bioprosthetic valves, respectively. Survival at 5 years was 61 +/- 7% (+/- the standard error) and 67 +/- 10% for recipients of mechanical valves and bioprosthetic valves, respectively. Male sex (p = 0.014) and urgency of operation (p = 0.006) were independent risk factors for hospital mortality. Atrial fibrillation increased valve-related mortality (p = 0.01). No patient required reoperation or experienced structural valve failure. While anticoagulant-related hemorrhage was increased in recipients of mechanical valves (9.2 +/- 2.1%/patient-year) compared with recipients of bioprosthetic valves (2.3 +/- 1.1%/patient-year), it did not result in a death or lead to permanent disability. There was no difference in freedom from any valve-related complication at 5 years. However, when all morbid events are considered, recipients of bioprosthetic valves experienced fewer valve-related complications than patients receiving mechanical valves (10.7 +/- 2.3%/patient-year versus 17.6 +/- 2.5%/patient-year, respectively; p less than 0.05). The reduced incidence of anticoagulant-related hemorrhage and the infrequent need for warfarin sodium anticoagulation favor selection of a bioprosthetic heart valve in patients older than 70 years.

Aged

Aortic disease associated with pregnancy.

Our experience with the management of two patients with life-threatening aortic disease during pregnancy is presented with a review of the literature. One of our patients had intimal disruption caused by trauma; the other had probable Ehlers-Danlos type IV syndrome, causing an acute dissection of the descending thoracic aorta and eventually requiring replacement of the aorta from the left subclavian artery to common iliac arteries. The challenge of treating both the pregnant woman and the fetus was managed successfully by an emergent cesarean section followed by Dacron graft replacement of the descending thoracic aorta. The literature reviewed disclosed that aneurysm expansion producing symptoms and dissection is most common during the third trimester and during labor and delivery in patients with or without Marfan's syndrome. Half of the aortic dissections in women less than 40 years of age occur in association with pregnancy. The available evidence indicates that patients with known valvular or aortic disease should have surgical repairs during the first or second trimester and thereafter have delivery by cesarean section. However, patients with acute aortic problems near term appear to be better managed by cesarean section followed promptly by treatment of the aortic disease.

Adult

New pluronic-free perfluorocarbon cardioplegia improves myocardial oxygenation.

Cardioplegic protection with oxygenated lecithin-emulsified methyl adamantane, a perfluorocarbon with high oxygen solubility, was compared with oxygenated crystalloid cardioplegic solution in an ischemic rabbit heart model. The cardioplegic solutions had identical salt compositions with a potassium concentration of 15 meq/l. Eighteen isolated rabbit hearts underwent 180 minutes of global ischemia at 30 degrees C, followed by a 45-minute period of reperfusion at 37 degrees C. During the ischemic period, cardioplegic solution was infused every 30 minutes, and myocardial oxygen extraction was calculated. Left ventricular function was assessed before and after ischemia by measuring left ventricular isovolumic developed pressure and the first derivative of pressure (dP/dt). Cardioplegia oxygen extraction for the methyl adamantane hearts was 230 +/- 11 ml of O2/100 g heart wt and 150 +/- 25 ml O2/100 g heart wt for the crystalloid hearts (p less than 0.05). Recovery of dP/dt at 30 minutes of reperfusion, expressed as a percentage of preischemic control, was 80% +/- 3% for the methyl adamantane hearts and 61% +/- 3% for the crystalloid hearts (p less than 0.05). The developed pressure for the methyl adamantane hearts was 73% +/- 3% and for the crystalloid hearts, 62% +/- 2% (p less than 0.05). In this global ischemia model, perfluorocarbon emulsified with egg-yolk phospholipid improved oxygen delivery and postischemic myocardial performance compared with an oxygenated crystalloid cardioplegic solution.

Animals

Predictors of perioperative mortality in patients with unstable postinfarction angina.

Factors associated with increased operative mortality in patients with postinfarction angina have not been defined. Two hundred twenty-five patients underwent urgent coronary artery bypass grafting from 1982 through 1986. One hundred sixty-two men and 63 women averaged 62 years of age (range, 35-87 years). Operative mortality was 5.3%. To assess the predictors of perioperative mortality, 16 variables were evaluated by univariate and multivariate analyses. Significant independent predictors of perioperative mortality were the presence of a transmural anterior myocardial infarction (p less than 0.0005) and the need for preoperative intra-aortic balloon pumping for angina or congestive heart failure (p = 0.009). All perioperative mortalities (12 patients) occurred in this subset (anterior myocardial infarction, intra-aortic balloon pumping, or both) that included 101 patients. The mean follow-up period was 27.8 months (range, 1-69 months). There were 11 late deaths, resulting in an actuarial survival of 92 +/- 2%, 91 +/- 2%, 88 +/- 2.6%, and 88 +/- 4% at 1,2,3, and 4 years, respectively. Ninety-six percent of survivors were assigned to New York Heart Association Class I or II for congestive heart failure, and 96% were assigned to Class I or II for angina. Urgent coronary artery bypass grafting can be performed in patients with unstable postinfarction angina with acceptable mortality, although a significant increase in risk exists for patients with preoperative transmural anterior myocardial infarction, intra-aortic balloon pumping, or both.

Adult

Ten-year analysis of the Björk-Shiley standard aortic valve.

Long-term performance characteristics of the Björk-Shiley standard aortic valve were determined by analyzing the follow-up of 514 patients undergoing operation between 1971 and 1981. Cumulative follow-up was 2,601 patient-years (average, 5.3 +/- 3.8 years); 53% (238/452) of hospital survivors have been followed more than 5 years. Valve-related complications expressed as both actuarial event-free percents (+/- standard error at 10 years) and first-event linearized determinations (percent per patient-year) occurred at the following rates: thromboembolism, 82 +/- 3 and 2.3 +/- 0.3, respectively; anticoagulant-related hemorrhage, 60 +/- 4 and 5.6 +/- 0.5; prosthetic valve endocarditis, 94 +/- 2 and 0.8 +/- 0.2; valve thrombosis, 97 +/- 1 and 0.4 +/- 0.1; reoperation, 94 +/- 2 and 0.6 +/- 0.2; valve failure, 82 +/- 4 and 1.6 +/- 0.2; and composite valve-related morbidity and mortality, 46 +/- 4 and 8.8 +/- 0.2. Overall survival was 72 +/- 2% at 5 years and 55 +/- 3% at 10 years; valve-related complications accounted for 22% of the late deaths. Although no instance of structural valve failure could be identified, 25% of valve-related complications resulted from valve failure, of which 67% were fatal. By 10 years, 54% of patients had experienced at least one form of major valve-related complication, 16% of which proved fatal. The Björk-Shiley standard aortic valve has late valve-related complications similar to other existing mechanical prostheses that have been subjected to long-term analysis.

Adult

The effects of age on outcome after coronary bypass surgery.

To study the effects of increasing age on outcome after coronary artery bypass grafting (CABG), 684 patients who underwent CABG from 1980 to 1985 were entered into a noncurrent prospective study. Patients were matched by date of operation and placed into three groups according to age: (1) 70 and older, (2) 55 to 69, or (3) less than 55. In addition to intraoperative and postoperative data collected on all patients, follow-up was obtained on 97% of the patients at a mean of 30 +/- 16 months. Older patients were more often female (p less than .002), and white (p less than .001) and had more preexisting cerebrovascular disease (p less than .0001), peripheral vascular disease (p less than .001), unstable angina (p less than .0001), and longer mean bypass pump times (p less than .001). Older patients had a higher hospital mortality (9.3% vs 2.2%), suffered more complications, including stroke, wound infection, reoperation for bleeding, need for intropic drug support, and prolonged ventilation, and had longer mean postoperative hospital stays (14 vs 9 days, p less than .0001). After discharge, mortality rates were similar in all groups, as was recurrence of symptoms and degree of rehabilitation. While patient age at operation significantly influenced hospital mortality and morbidity, this appeared to be a consequence of the greater frequency of risk factors in patients over 70 years of age. In addition, late follow-up failed to demonstrate any significant differences based on age alone in survival or functional status among patients undergoing CABG.

Activities of Daily Living