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M T Swartz

Publications and source records attributed to M T Swartz.

At least 19 recordsLinked to original sources
PubMed2001

Risk analysis in patients bridged to transplantation.

BACKGROUND: Efforts to predict mortality in bridge to cardiac transplant patients have concentrated on preventricular assist device (VAD) status. To more fully identify factors influencing survival to transplant, we reviewed the preoperative and postoperative VAD courses of 105 bridge to transplant patients. METHODS: Sixty-four parameters (34 pre-VAD, 30 post-VAD), including hemodynamics, complications, and evaluations of major organ function were examined and analyzed. RESULTS: Thirty-three patients (31%) died on VADs and 72 were transplanted. There were two posttransplant operative deaths (3%). By univariate analysis 23 of 64 factors were significant. These 23 factors were entered into a stepwise logistic regression analysis to identify predictors of survival to transplant. Four factors, including pre-VAD intubation (p < 0.005), cardiopulmonary bypass (CPB) time during VAD insertion (p < 0.0001), mean pulmonary artery pressure (first postoperative day after VAD) (p < 0.0002), and highest post-VAD creatinine (p < 0.01) were independent predictors of transplantation. CONCLUSIONS: Other than the need for intubation, pre-VAD variables were of little value in predicting survival to transplant. Problems during VAD insertion (long CPB time) and post-VAD renal insufficiency were independent predictors. Severe complications that developed during the interval of VAD support, including cerebrovascular accident, bleeding and infection, were surprisingly not predictors for transplantation.

Actuarial Analysis↗
PubMed2001

Surgical treatment of early-stage breast cancer in the Department of Defense Healthcare System.

BACKGROUND: The choice between breast-conserving surgery and modified radical mastectomy in the treatment of women with early stage breast cancer in the Department of Defense Healthcare System may be influenced by demographic factors. STUDY DESIGN: The Department of Defense Automated Central Tumor Registry (ACTUR) was queried for women diagnosed with American Joint Committee on Cancer Stage I or II invasive breast carcinoma from January 1, 1986, to December 31, 1996. Univariate analysis and multivariate analysis were applied to the study variables. Year of diagnosis, age at diagnosis, tumor size, type of hospital, geographic region, and local availability of radiation therapy were evaluated with respect to the type of surgical treatment performed. Surgical treatment was either breast conservation therapy (BCT) or modified radical mastectomy. RESULTS: After excluding women for whom the data were incomplete (n = 308), 7,815 women were identified who met study criteria. There was a progressive increase in the use of BCT to treat tumors of all sizes from 16% to 47% over the 11 years of the study (p < 0.0001). BCT was more frequently used for smaller tumors (< 2cm), with an odds ratio of 2.46 (2.20-2.76, 95% CI). In 1996, 54% of women with T1 (< 2 cm) tumors were treated with BCT. Women treated with BCT were nearly the same age as those undergoing modified radical mastectomy (55.5 years versus 56.8 years, p < 0.0001). BCT was used at a slightly greater rate in medical centers than in community hospitals (31% versus 28%, p < 0.0001). Use of BCT varied among geographic regions from a low of 24% in the southwestern USA to a peak of 36% in the Northeast and 40% in hospitals outside of the continental United States (p < 0.0001). Local availability of radiation therapy did not influence choice of treatment. CONCLUSIONS: The use of BCT to treat early stage invasive breast carcinoma in the Department of Defense Healthcare System is increasing. But BCT is used less often to treat larger tumors. Regional differences in the use of BCT persist, even after controlling for other factors. Patient age and type of hospital (community versus academic center) appear to exert little influence on the choice of treatment. Local availability of radiation therapy did not seem to influence the choice of treatment. Our data suggest that efforts to promote the use of BCT should target the central and southwestern USA. Use of BCT should also be emphasized for women with larger tumors (> 2 cm).

Aged↗
PubMed2000

Major leg wound complications after saphenous vein harvest for coronary revascularization.

BACKGROUND: Major leg wound complications after coronary artery bypass graft procedures are infrequent and few are reported in the literature. We present our experience in treating 23 patients with major leg wound complications after coronary revascularization procedures. METHODS: A retrospective review of 3,525 bypass procedures with saphenous vein grafts performed over a 10-year period was conducted. Ten potential risk factors for those who developed major leg wound complications were analyzed and compared with the entire cohort of patients undergoing similar bypass procedures during the same period. RESULTS: Lower extremity wound complications occurred in 145 patients (4.1%), 23 of whom (0.65%) required additional surgical interventions (62 total). There were 32 wound debridements, 8 skin grafts, 11 vascular procedures, 5 amputations, 3 fasciotomies, 2 free tissue transfers, and 1 fasciocutaneous flap. Of ten variables evaluated by multivariate analysis, female gender, peripheral vascular disease, and postoperative intraaortic balloon pump use were identified as significant independent predictors of major leg wound complications (p < 0.0001). CONCLUSIONS: The causes of major leg wound complications after saphenous vein harvest for coronary artery bypass graft procedures are multifactorial. To minimize these complications, we recommend vascular evaluations before saphenous vein harvest, attention to proper surgical technique, and careful harvest site selection.

Aged↗
PubMed2000

Transfer of patients receiving advanced mechanical circulatory support.

OBJECTIVE: Improving results with ventricular assist devices have led to their wider clinical application. Centers can stabilize, support, and wean or transfer patients to regional transplant centers. METHODS: Prospectively collected data were reviewed to evaluate the clinical results of patients transferred to our institution while receiving advanced mechanical circulatory support. RESULTS: Since 1993, 16 patients were accepted while receiving support with either extracorporeal membrane oxygenation or a ventricular assist device. The 10 male and 6 female patients ranged in age from 9 to 60 years (mean, 42.1 years). Thirteen had had cardiac surgical procedures, two had acute myocardial infarctions, and one had myocarditis. The distance transported ranged from 0.2 to 309 miles (mean, 132 miles). Twelve patients were transferred by ground, and 4 were transported by air. Seven patients were originally supported with extracorporeal membrane oxygenation, 6 with centrifugal pumps, and 3 with ABIOMED ventricular assist devices (ABIOMED, Inc, Danvers, Mass). Two patients had clinical complications during transfer, and one had a cerebrovascular accident, recovered, was weaned, and survived. A second patient had hemodynamic deterioration. There were no technical complications associated with transport. Six patients were left on the original support device; 3 of the 6 were weaned and survived, and 3 died during support. The 10 remaining patients were switched to other ventricular assist devices: 9 patients to Thoratec devices (Thoratec Laboratories, Pleasanton, Calif) and 1 patient to a Novacor device (Baxter Healthcare Corp, Novacor Division, Oakland, Calif). Six of the 10 patients underwent transplantation and survived. Four patients died while being supported by the devices. Nine patients were discharged, with 1 late death at 29 months. Eight patients are alive 4 to 65 months after discharge. CONCLUSIONS: These data suggest that patients receiving advanced support can be moved between clinical centers with acceptable risks. Because 33% of the survivors were weaned, transplantation is not required for survival.

Adolescent↗
PubMed1999

Clinical experience with 111 thoratec ventricular assist devices.

BACKGROUND: Ventricular assist devices (VADs) have gained wider acceptance due to refinements in patient selection and management and device availability. METHODS: To evaluate early and late results, we reviewed our first 111 patients with the Thoratec VAD. RESULTS: Forty-four patients were supported for myocardial recovery. The mean age in the recovery group was 51.9 years. There were 18 left VADs (LVADs), 17 biventricular VADs (BVADs), and nine right VADs (RVADs). Complications included bleeding in 20 patients (45%) and device-related infection in 1 patient (2%). Nineteen were weaned from the VAD, with 12 survivors. Sixty-seven patients were supported as a bridge to cardiac transplantation. The mean age was 41.5 years. There were 39 LVADs and 28 BVADs. Complications included bleeding in 21 patients (31%) and device-related infection in 12 (18%). Three patients were weaned and 39 patients were transplanted from the assist device, for a total of 42 bridge survivors. Device-related thromboembolism occurred in 9 patients (8.1%), 7 of whom were bridge to transplantation. The duration of VAD support ranged from 0.1 to 27 days (mean 4.5 days) in the recovery group and 0.2 to 184 days (mean 40.7 days) in the bridge to transplantation group. The 10-year actuarial survival was 16% for the recovery group, 22%, for the bridge group, and 33% for transplanted patients. CONCLUSIONS: Despite advances, VAD support remains associated with significant morbidity and operative mortality.

Adolescent↗
PubMed1999

Ventricular assist device support in patients with mechanical heart valves.

BACKGROUND: Due to potential thromboembolic complications, mechanical valves within the native heart are often considered contraindications to ventricular assist device (VAD) support. METHODS: A retrospective review of VAD cases between June 1982 and March 1998 showed 8 patients with mechanical valves who were supported with Thoratec (Pleasanton, CA) VADs. RESULTS: There were 6 males and 2 females ranging in age from 20 to 69 years (mean 49.8+/-5.6). Four patients were supported when they could not be weaned from cardiopulmonary bypass after reparative procedures and were thought to have reversible injuries. Four patients were supported as a bridge-to-cardiac transplantation. Two patients had mechanical mitral valves, 2 had aortic valve replacements, 1 had an aortic homograft and mechanical mitral valve, 2 had mechanical aortic and mitral prosthesis, and 1 patient had aortic, mitral, and tricuspid valves. The types of valvular prostheses were St. Jude (5 patients) and Bjork-Shiley (3 patients). Duration of support ranged from 3.0 to 150 days (mean 34 days). Four patients were supported with biventricular assist devices and 4 had left VADs. Dextran and intravenous heparin anticoagulation were used in the shorter duration patients, with warfarin being used in the bridge patients. One patient received warfarin and aspirin. At the time of autopsy or device removal, only 1 of the 12 mechanical intracardiac valves showed any evidence of thrombosis, including the aortic valves in 2 patients supported for 2 and 5 months. There were no clinical thromboembolic events. Four patients (50%) were discharged (1 weaned, 3 transplanted). CONCLUSIONS: The 50% (4 of 8) survival rate compares favorably with the 44% (41 of 92) overall survival rate for our Thoratec patients (bridge plus recovery) who did not have mechanical prosthetic valves. These data suggest that patients with mechanical intracardiac valves can be supported for short durations with some additional risk, which is yet to be determined.

Adult↗
PubMed1998

Right ventricular infarction during left ventricular assist system support.

Left ventricular assist devices are frequently used to bridge patients to cardiac transplantation. As this experience grows, new and unanticipated complications will occur. This report describes a 50-year-old man with ischemic cardiomyopathy being bridged to cardiac transplantation who suffered an acute right ventricular infarction during the interval of support.

Fatal Outcome↗
PubMed1998

Intermittent antegrade tepid versus cold blood cardioplegia in elective myocardial revascularization.

BACKGROUND: The ideal temperature for blood cardioplegia administration remains controversial. METHODS: Fifty-two patients who required elective myocardial revascularization were prospectively randomized to receive intermittent antegrade tepid (29 degrees C; group T, 25 patients) or cold (4 degrees C; group C, 27 patients) blood cardioplegia. RESULTS: The two cohorts were similar with respect to all preoperative and intraoperative variables. The mean septal temperature was higher in group T (T, 29.6 degrees +/- 1.1 degrees C versus 17.5 degrees +/- 3.0 degrees C; p < 0.0001). After reperfusion, group T exhibited significantly greater lactate and acid release despite similar levels of oxygen extraction (p < 0.05). The creatine kinase-MB isoenzyme release was significantly lower in group T (764 +/- 89 versus 1,120 +/- 141 U x h/L; p < 0.04). Hearts protected with tepid cardioplegia demonstrated significantly increased ejection fraction with volume loading, improvement in left ventricular function at 12 hours, and decreased need for postoperative inotropic support (p < 0.05). The frequency of ventricular defibrillation after cross-clamp removal was lower in this cohort (p < 0.05). There were no hospital deaths, and both groups had similar postoperative courses. CONCLUSIONS: Intermittent antegrade tepid blood cardioplegia is a safe and efficacious method of myocardial protection and demonstrates advantages when compared with cold blood cardioplegia in elective myocardial revascularization.

Aged↗
PubMed1998

Mitral valve replacement: randomized trial of St. Jude and Medtronic Hall prostheses.

BACKGROUND: This study was designed to better define the merits of the bileaflet and tilting-disc valves. METHODS: We prospectively randomized 156 patients (mean age, 59 years) to receive either the St. Jude (n = 80) or the Medtronic Hall (n = 76) mitral valve prosthesis between September 1986 and December 1997. The two groups were not significantly different with respect to preoperative New York Heart Association class, left ventricular ejection fraction, incidence of mitral stenosis or insufficiency, extent of coronary artery disease, completeness of revascularization, or cross-clamp or bypass time. RESULTS: The operative mortality (11.2% versus 13.1%, St. Jude versus Medtronic Hall, respectively) and late mortality (27% versus 22%, St. Jude versus Medtronic Hall, respectively) were not significantly different. Follow-up was complete in all hospital survivors with a mean of 60.7 months (range, 1 to 133 months). The analysis of 10-year actuarial survival and freedom from valve-related events demonstrated no significant differences between the cohorts. Freedom from reoperation was higher in the St. Jude group (p < 0.01). Comparisons of patient functional status and echocardiographic hemodynamic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. CONCLUSIONS: This study suggests that there is no difference between the St. Jude and Medtronic Hall prostheses with respect to late clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.

Aged↗
PubMed1998

Cardiac assist devices.

During the latter half of the twentieth century, physicians have had the capability to support the circulation with mechanical devices. This article gives an historical overview of those devices. Various devices and their complications are described and evaluated. Patient selection and clinical results also are discussed.

Adult↗
PubMed1996

Management of asymptomatic mild aortic stenosis during coronary artery operations.

BACKGROUND: Management of asymptomatic mild aortic stenosis at the time of coronary artery bypass grafting (CABG) remains controversial. We have retrospectively analyzed a cohort of patients requiring aortic valve replacement (AVR) subsequent to CABG and compared their operative morbidity and mortality with that of a group receiving CABG and AVR simultaneously at the first operation. METHODS: Analysis is drawn from 28 patients who required AVR 8 +/- 4 years subsequent to CABG (group A) and 175 patients receiving AVR along with CABG at the primary operation (group B). Groups were similar with respect to age, sex, risk factors for cardiac disease, extent of coronary artery disease, left ventricular function, New York Heart Association class, aortic valve area, number of grafts, and size of prosthesis inserted. RESULTS: Patients having AVR subsequent to CABG had a significantly prolonged aortic cross-clamp time and global myocardial ischemic time and incurred a twofold increase in operative mortality. The actuarial survival at 10 years was not significantly different between cohorts. In the 28 patients in group A, the aortic valve area during the period between operations decreased 0.05 mm2/y. CONCLUSIONS: The operative mortality and morbidity of a second operation for AVR is high, but there is no significant difference in survival at 10 years. In at least a portion of patients having mild aortic stenosis at the time of CABG there will be progression of the stenosis necessitating reoperation at a later date.

Actuarial Analysis↗
PubMed1996

Effect of triiodothyronine on graft function in a model of heart transplantation.

BACKGROUND: Brain death is associated with neuroendocrine changes that result in impaired metabolism, reduced myocardial energy stores, and deteriorating cardiac function. As a result of these changes, a substantial number of normal human hearts are not considered suitable for transplantation. In the hope of preventing these complications and stabilizing the condition of cardiac donors, we compared the function of transplanted hearts from brain-dead rats that received triiodothyronine (T3) (n = 6) with that of hearts from a group that received a placebo (n = 5). METHODS: This experiment was designed to be both blinded and randomized. Brain death was achieved by bilateral carotid ligation and inflation of an intracranial balloon. Triiodothyronine or placebo was administered in a blinded, randomized fashion. The brain-dead donors were then supported with conventional techniques for 2 hours after which time heterotopic transplantation was performed using hypothermic preservation and a working heart model. Hemodynamics of the transplanted hearts were assessed 48 hours postoperatively. RESULTS: The hearts from donors that had been pretreated with T3 were found to have a significantly higher (p < 0.005) peak left ventricular pressure than the hearts from the placebo-treated group (137 +/- 17 mm Hg versus 115 +/- 15 mm Hg). Left ventricular end-diastolic pressure was significantly lower (p < 0.01) in the T3-treated group (5.2 +/- 2.2 mm Hg) compared with the placebo-treated group (6.9 +/- 0.5 mm Hg). There was also a significantly higher (p = 0.03) maximal first derivative of left ventricular pressure in the T3-treated group compared with the placebo-treated group (4,876 +/- 1,348 mm Hg/s versus 3,344 +/- 1,016 mm Hg/s). Finally, the cardiac output in the group given T3 was 93 +/- 16 mL/min compared with 61 +/- 22 mL/min in the group given the placebo (p < 0.01). CONCLUSIONS: Hearts from brain-dead rats that had received T3 before transplantation showed improved postoperative function. The experimental design of predonation brain death, cold immersion storage, and transplantation in a working heart model should make these data more relevant clinically than those previously reported.

Abdomen↗
PubMed1996

Changes of intraaortic balloon volume during pumping in a mock circulation system.

The effects of hemodynamic changes on intraaortic balloon (IAB) volumes were studied experimentally using a helium tachometer in a mock circulatory system. The IAB volume decreased with increases in the heart rate and mean aortic pressure, but the degree of reduction in the IAB volume was different among 4 commercially available IAB drivers. Improvements in IAB consoles are needed to compliment the progress made in percutaneous techniques for IAB insertion resulting in smaller balloons.

Arrhythmias, Cardiac↗
PubMed1996

Optimal control algorithm for pneumatic ventricular assist devices: its application to automatic control and monitoring of ventricular assist devices.

We developed a control and monitoring unit for pneumatic ventricular assist devices (VADs), which provides optimal fill and empty control and real-time evaluation of pump performance. The flow signal of the inflow cannula is integrated every beat to yield pump filling volume per pump diastole. The ejection signal is triggered when pump filling reaches a preset level. The instantaneous mean flow of each beat (stroke volume/cycle length) is compared with the previous beat, and the threshold level is readjusted to optimize flow. This feedback loop is repeated every beat, and pump filling is immediately adjusted to yield maximum pump flow. Simultaneously the mean flow of every 10 beats is compared with that of the previous 10 beats; then, the ejection time is readjusted to optimize flow. Initial clinical application of this unit supports its effectiveness and reliability.

Aged↗
PubMed1995

Double-valve replacement with Medtronic-Hall or St. Jude valve.

To define better the performance of the bileaflet St. Jude and the tilting-disc Medtronic-Hall valves, we retrospectively analyzed 122 patients (St. Jude, 80 patients; Medtronic-Hall, 42 patients) who received simultaneous aortic and mitral replacement from May 1984 until June 1994. The two groups were not different with respect to preoperative clinical and hemodynamic parameters and New York Heart Association functional class. The hospital mortality and late mortality were not significantly different. Risk analysis identified advanced age and previous myocardial revascularization as predictors of operative death. Follow-up was complete in 96 of 103 hospital survivors (93%) and was similar in both groups. The actuarial survival, linearized rates of valve-related complications, and actuarial freedom from valve-related complications were similar in both cohorts. The presence of coronary artery disease negatively influenced the actuarial survival after simultaneous aortic and mitral valve replacement. Postoperative New York Heart Association functional class was not significantly different in either group. These data indicate that the Medtronic-Hall and St. Jude prostheses are not significantly different with respect to their clinical performance and valve-related complications for simultaneous double-valve replacement.

Aortic Valve↗
PubMed1994

Risk stratification in patients bridged to cardiac transplantation.

Patient selection is considered one of the most important factors influencing success in bridge to transplant procedures. However, to date it has been difficult to identify predictors of mortality in this population using univariate or multivariate analysis. In 1988, we developed a scoring system using 21 clinical variables that could be calculated rapidly at the bedside while evaluating potential candidates. Points were designated to these variables using a scale of 1 to 3, 1 having the least adverse effect on survival and 3 the most. Patients received a value of 0 for each variable that did not apply. This scoring system was used in a retrospective analysis for 15 bridge to transplant patients. The results showed a significant difference (p < 0.003) between the 8 survivors (mean score, 5.75 +/- 2.19) and the 7 nonsurvivors (mean score, 11.71 +/- 3.45). Since 1989, we have prospectively calculated the scores in an additional 27 patients. Based on the score, all 42 patients were divided into three groups: group I had scores of 1 to 5; group II, 6 to 10; and group III, 11 to 16. The mean score for group I (16 patients) was 3.69 +/- 1.25. All group I patients survived. Group II patients (n = 15) had a mean score of 7.87 +/- 1.36 and a survival rate of 53%. The mean score for group III (n = 11) was 13 +/- 1.73. Thirty-six percent of these patients survived. Comparison of survival and mean scores among the three groups was statistically significant (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗