Primary cardiac carcinosarcoma: a rare, aggressive tumor.

Primary cardiac carcinosarcoma is a rare cardiac tumor, and little is known about its natural history. We treated a man who had no evidence of a cardiac mass at initial echocardiography, but 19 months later he had a large biatrial tumor with left ventricular inflow obstruction. Only palliative resection could be achieved. Four months postoperatively extensive tumor recurrence was found, and he died a month later. Histologic examination showed cells with features of both rhabdomyosarcoma and adenocarcinoma, and the tumor was classified as a primary cardiac carcinosarcoma.

Endocarditis as the first presentation of AIDS in infancy.

A two month old Ugandan boy underwent surgery for an obstructive right ventricular vegetation associated with disseminated Staphylococcus aureus infection. Both the child and his mother subsequently tested positive for HIV infection. Very little is know about the incidence of endocarditis in paediatric patients with AIDS. To our knowledge this is the first case reported of disseminated S aureus infection associated with endocarditis and an obstructing vegetation in an HIV positive infant with a structurally normal heart. The initial signs and symptoms for endocarditis were atypical, a reflection of the overwhelming infection in an immunocompromised patient. Severe infections may have an atypical presentation in immunosuppressed patients. AIDS needs to be considered in these patients, especially if they come from populations with endemic HIV infection.

Intramural blood flow of skeletal muscle ventricles functioning as aortic counterpulsators.

BACKGROUND: Skeletal muscle ventricles (SMVs) working as aortic counterpulsators have provided long-term left ventricular assistance under experimental conditions. However, gradual deterioration of SMV pump function and rupture have been observed, and this may be related to compromised intramural blood flow during synchronized counterpulsation under systemic working conditions. METHODS: Transformed, double-layered SMVs in 6 sheep were stimulated for 3-minute periods (5 V, 30 Hz, burst duration and delay from QRS both 40% of the cardiac cycle) to work as diastolic counterpulsators in the systemic circulation at a 1:2 (SMV:heart) and 1:1 ratio, and on a mock circulation with low-pressure loading conditions at a 1:2 ratio. Thoracodorsal artery blood flow was monitored by ultrasonic flow probe, and intramural blood flow distribution was investigated by fluorescent microspheres. Thoracodorsal venous lactate concentrations were measured before and after each period of stimulation. RESULTS: Thoracodorsal artery blood flow increased significantly (p < 0.001) after stimulation. The magnitude of augmentation (89%; 95% confidence interval, 36% to 163%) was similar for all working conditions studied. Reactive hyperemia was observed after most 1:1 regimens but was rare after 1:2 regimens. A significant (p < 0.05) 15% increase in serum lactate levels was present after 1:1 regimens only. All regimens of stimulation resulted in a significant increase (p < 0.01) in blood flow to sections in the outer wall of the SMV, but a significant increase (p < 0.05) in blood flow to sections in the inner wall was observed only under low loading conditions. CONCLUSIONS: Skeletal muscle ventricles subjected to 1:1 systemic counterpulsation regimens work under partly anaerobic conditions. High loading conditions may compromise SMV inner wall blood flow.

Assessment of skeletal muscle ventricle function using tissue velocity imaging.

BACKGROUND AND AIMS: Skeletal muscle ventricles (SMVs) are a potential power source for circulatory assistance. Noninvasive assessment of SMVs is desirable in long-term studies of SMV function. This study evaluated whether tissue velocity imaging (TVI) indices of function correlate with invasive measurements of output and pressure generation and examined the potential of TVI to provide information about SMV geometry and wall contraction characteristics. METHODS: SMVs were constructed in six sheep. After electrical conditioning, SMVs were connected to a mock circulation and stimulated with supramaximal 30-Hz and 50-Hz bursts to contract 35 times/min. The SMVs were tested over a range of preloads, and afterload was adjusted to simulate systemic (80 mmHg) and right ventricular (30 mmHg) loading conditions. Stroke volume and pressure were measured invasively, and stroke work was calculated. TVI was used to measure velocities in two opposing SMV walls, providing a simple wall motion score (WMS). This was evaluated against stroke volume, stroke work, and pressure development. RESULTS: 50-Hz stimulation frequency and high preload optimized SMV performance. Optimal SMV performance indices (mean at 50 Hz) were as follows: (a) right ventricular loading conditions (preload 30 mmHg), stroke volume 17.6 mL (SEM 3.2), peak pressure over afterload 44.2 mmHg (10.9), stroke work 0.05 J (0.02); (b) systemic loading conditions (preload 60 mmHg), stroke volume 10.1 mL (3.2), peak pressure over afterload 58 mmHg (14.6), stroke work 0.08 J (0.03). With low preloads, geometric anomalies were noted in the SMVs using TVI. Collapse of the SMVs and dyskinesis were observed, which normalized with higher preloads. Persistent dyskinesis was noted in one SMV and was associated with poor performance. Correlations (at optimal loading and stimulation settings) were as follows: systemic loading conditions, stroke volume versus WMS, 0.92 (p = 0.026); peak pressure versus WMS 0.89 (p = 0.045); stroke work versus WMS, r = 0.91 (p = 0.046). Right ventricular loading conditions were as follows: stroke volume versus WMS, 0.63 (p = 0.25); peak pressure versus WMS, 0.66 (p = 0.22); stroke work versus WMS, 0.45 (p = 0.39). CONCLUSION: Under systemic loading conditions, TVI indices of SMV wall motion mirror invasive indices of performance, suggesting that TVI may be a useful tool for long-term noninvasive monitoring of SMV function.

Effects of cardiomyoplasty on cardiac growth in rats.

BACKGROUND AND AIM OF THE STUDY: Cardiomyoplasty (CMP) has been proposed as a treatment for pediatric patients, but restriction of cardiac growth by the muscle wrap is a potential source of concern. This possibility was investigated in an immature animal model. METHODS: Six-week-old rats (body weight 203.8 +/- 5.4 g, mean +/- SEM) underwent either left thoracotomy with CMP (group I, n = 7), or thoracotomy without CMP (group II, n = 8). A third group (group III, n = 7) served as untreated controls. Final measurements were made 20 weeks later after body weights had reached a plateau. RESULTS: Preoperative body weights were not significantly different between the groups. At elective sacrifice, the body weights of animals that underwent surgery did not differ significantly (group I, 558.0 +/- 21.5 g and group II, 617.3 +/- 20.3 g), but were significantly less than those of control animals (727.6 +/- 13.3 g, p < 0.001 and p < 0.01, respectively). Cardiac ventricular weights in the CMP group were significantly less than those of control animals (group I, 1.21 +/- 0.06 g; group III 1.45 +/- 0.04 g; p < 0.01), but were not statistically different from those of the sham thoracotomy group (group II, 1.36 +/- 0.05 g). Mean left ventricular end-diastolic volumes were similar in all groups (group I, 0.67 +/- 0.07 mL; group II, 0.66 +/- 0.07 mL; and group III, 0.69 +/- 0.10 mL; p = ns). CONCLUSIONS: A major surgical procedure impairs growth in juvenile rats. no evidence emerged from this study for additional restriction of cardiac development due to cardiac wrapping. However, studies that include stimulated muscle wraps are needed before CMP should be considered for the pediatric age group.

Controlled pressure reperfusion of rat pulmonary grafts yields improved function after twenty-four-hours' cold storage in University of Wisconsin solution.

BACKGROUND: Pulmonary graft recipients commonly have a degree of pulmonary hypertension. Immediate reperfusion of stored pulmonary grafts at supraphysiologic or even physiologic pressures may be detrimental to subsequent function. We wished to test the hypothesis that initial reperfusion of pulmonary grafts at low pressures may be beneficial. METHODS: We used an isolated, ventilated rat lung model, perfused by an extracorporeal veno-venous circuit from a support animal. Three groups of donor lungs (n = 5 each) were flushed with cold University of Wisconsin solution. Group I was reperfused immediately at physiologic pressure to provide control values. Group II grafts were stored at 4 degrees C for 24 hours and reperfused at physiologic pressure. Group III grafts were also stored at 4 degrees C for 24 hours but reperfused according to a protocol of reduced pressure initially, with increments every 15 minutes up to physiologic levels by 60 minutes. Grafts and support animals were ventilated with room air. Graft function was assessed over a 2-hour period with regard to oxygenation, vascular resistance, peak airway pressure, and the wet/dry weight ratio. RESULTS: Grafts in group II functioned poorly at 2 hours compared with control values: group II: oxygen tension 68 +/- 4 mm Hg; pulmonary vascular resistance 2488 +/- 675 x 10(3) dyne.sec/cm5; peak airway pressure 32 +/- 1 mm Hg wet/dry wright ratio 9.1 +/- Group I: oxygen tension 136 +/- 2 mm Hg; pulmonary vascular resistance 120 +/- 3 x 10(3) dyne.sec/cm5; peak airway pressure 13 +/- 1 mm Hg and wet/dry weight ratio 3.6 +/- 0.3; p < 0.001 all parameters except pulmonary vascular resistance: p < 0.05. In contrast, grafts undergoing controlled pressure reperfusion (group III) achieved function comparable with baseline values at 2 hours: oxygen tension 137 +/- 3 mm Hg; pulmonary vascular resistance 132 +/- 7 x 10(3) dyne. sec/cm5; peak airway pressure 13 +/- 1 mm Hg; wet/dry weight ratio 4.1 +/- 0.3 (p = Not significant). CONCLUSIONS: The pressure at which pulmonary grafts are initially reperfused appears to be critical to their subsequent integrity. A protocol of controlled reperfusion may reduce reperfusion injury and improve graft function in clinical practice.

Latissimus dorsi muscle blood flow during synchronized contraction: implications for cardiomyoplasty.

BACKGROUND: Damage in latissimus dorsi muscle flaps has been reported after clinical and experimental cardiomyoplasty, and an ischemic origin has been suggested. METHOD: In situ, preconditioned latissimus dorsi muscles in 5 sheep were stimulated in either 1:1 (muscle: heart) or 1:2 synchrony with the systolic phase of the cardiac cycle, using a burst duration of either 21% or 35% of the cycle. Thoracodorsal artery blood flow and thoracodorsal venous lactate concentrations were measured before and immediately after a 3-minute period of stimulation. RESULTS: The exercise-induced augmentation of thoracodorsal artery blood flow was significantly (p < 0.05) less with a 1:2 regimen than a 1:1 regimen, for both a 21% (88%; 95% confidence interval [CI], 55.6% to 127.3% versus 138.9%; CI, 97.6% to 188.8%) and 35% burst duration (123.2%; CI, 84.7% to 169.9% versus 167.0; CI, 120.8% to 222.6%). After cessation of stimulation, reactive hyperaemia was observed in 3 of 5 animals with 1:1 21% burst stimulation, and in 5 of 5 animals with a 35% burst duration, but was not seen after 1:2 regimens. A significant (p < 0.01) increase in thoracodorsal venous lactate levels was present after 1:1 35% burst stimulation (34.9%; CI, 9.9% to 65.6%), but lactate levels tended to fall when a 1:2 ratio was used (15.9%; CI, -3.2% to 31.5%; p < 0.1). CONCLUSIONS: One-to-one stimulation regimens may be detrimental to latissimus dorsi blood flow, and an adaptive, rather than fixed, burst duration may be preferable. These findings have important implications for the cardiomyoplasty procedure.

Mitral valve replacement with the Carpentier-Edwards standard bioprosthesis: performance into the second decade.

From March 1978, 196 Carpentier-Edwards standard bioprostheses (stCE) were implanted in 194 patients. There were 154 isolated mitral valve replacements (MVR) and 42 aortic plus mitral valve replacements (AVR/MVR) with a mean follow-up of 7.05 (range 0-15.2) years and 7.15 (range 0-13.8) years, respectively. Freedom from structural valve failure at 10 years was 70.8% +/- 4.9% (MVR) and 59.6% +/- 11.1% (AVR/MVR). The incidence of structural valve failure increased sharply after 7 years. Freedom from thromboembolism was 83.0% +/- 3.8% (MVR) and 89.0 +/- 6.0% (AVR/MVR). Thromboembolic events were related to the presence of atrial fibrillation in patients not receiving anticoagulation. Anticoagulant-related haemorrhage was rare. Freedom from mitral valve prosthetic endocarditis at 10 years was 90.9% +/- 3.1% (MVR) and 86.1% +/- 8.4% (AVR/MVR). Prosthetic valve endocarditis was associated with more than 60% mortality. The probability of event-free survival at 10 years follow-up was 43.6% +/- 4.6% (MVR) and 33.3% +/- 8.6% (AVR/MVR). The performance of the stCE in the mitral position shows a low rate of thromboembolic events and anticoagulant-related haemorrhage, but the long-term performance of the prosthesis is unsatisfactory due to a high rate of structural valve failure. This confirms earlier reports.

Cardiac rupture after thrombolytic therapy: the use of aprotinin to reduce blood loss after surgical repair.

Emergency cardiac surgery after recent thrombolytic therapy is associated with increased blood loss. A patient underwent emergency repair of a ruptured left ventricle after intravenous streptokinase treatment for acute coronary occlusion. High dose aprotinin was given during the operation to reduce the expected blood loss. Surgical repair was successful without bleeding complications. Total postoperative blood loss was 365 ml.