Management of locoregional stage esophageal cancer: a single center experience.

Therapeutic options for locoregional esophageal cancer (EC) include primary surgery, neoadjuvant or definitive chemoradiation and systemic chemotherapy. The role of surgery in these multimodal strategies has recently been debated and definitive chemoradiation is being offered as an alternative to surgery at many centers. We examined our results with multimodal therapy and surgery in this patient population. We conducted a retrospective analysis of 172 patients with locoregional (AJCC stages I-III) EC treated at RPCI between February 14, 1990 and September 20, 2002. Median age was 65 years (range, 36-95); there were 136 male patients. There were 100 regional (stages IIB-III), 69 local (stages I-IIA) and three in situ cases. Initial therapy was either combined modality (n = 122) or single modality (surgery) (n = 50). There was 0%, 30-day, postoperative mortality. Median survival for all patients was 25.3 months and was better for local stage with surgery alone (75 months) than with neoadjuvant (35.7 months) or definitive chemoradiation (19.1 months, P < 0.001). Survival for patients with regional disease treated with surgery alone, neoadjuvant or definitive chemoradiation was 21.5, 24.4 and 11.8 months, respectively (P = not significant). The associations of prognostic factors with overall survival were evaluated using Cox proportional hazards regression analysis and 2-sided Wald's chi-square test. On multivariate analysis, carefully selected patients treated with surgery alone had better outcomes compared with those treated with definitive chemoradiation (P < 0.001). Patients with locoregional esophageal cancer who are eligible for surgical resection either alone or as a part of multimodal therapy may have better outcomes than those treated with non-surgical approaches.

Should preoperative, post-chemoradiotherapy endoscopy be routine for esophageal cancer patients?

Chemoradiation therapy is used widely for locoregional esophageal cancer. Patients with persistent disease may benefit from surgery. Preoperative esophagoscopy can identify persistent tumor but its accuracy is uncertain. The primary objective of this study is to assess the extent of agreement between esophagoscopy and surgical pathology in patients treated with neoadjuvant chemoradiation. A retrospective chart review of patients who underwent chemoradiation, preoperative endoscopy and surgery from January 1996 to December 2002 was performed. Cohen's kappa statistic was used to measure the degree of agreement between findings at endoscopic biopsy and surgical pathology. Thirty cases were identified. All patients received chemoradiation followed by surgical resection. There was insufficient agreement between tumor size (kappa 0.25, standard error 0.17, P = 0.07) and appearance (kappa 0.19, standard error 0.18, P = 0.14). Preoperative endoscopy revealed atypia/inflammation in 15 cases and dysplasia in eight. Of these 23 cases, 11 were adenocarcinomas at surgery. Only nine patients had concurrence between surgical pathology and endoscopy. The positive and negative predictive values of esophagoscopy for identifying residual tumor were 100% and 11%, respectively. Our data suggests that after chemoradiation, esophagoscopy is unreliable for excluding residual disease. The roles of other modalities need to be explored.

Controversies in the multimodality management of locally advanced esophageal cancer: evidence-based review of surgery alone and combined-modality therapy.

Most patients with esophageal cancer present with locoregional disease, and the optimal initial management is controversial. The current National Comprehensive Cancer Network (NCCN) practice guidelines support diverse treatment options for locoregional disease, including surgical resection alone, definitive chemoradiation therapy, and preoperative combined-modality (neoadjuvant/trimodality) therapy. Many cancer centers worldwide favor a neoadjuvant approach, although the evidence supporting this practice is inconsistent. A concise review of the literature is presented. The topics discussed do not necessarily reflect each author's opinions or clinical practices.

Tracheostomy: a risk factor for mediastinitis after cardiac operation.

BACKGROUND: We studied whether tracheostomy after coronary artery bypass grafting (CABG) is associated with higher incidence of mediastinitis and mortality, and whether shorter intervals between median sternotomy and tracheotomy are associated with higher incidence of mediastinitis. METHODS: Patients (n = 6,057) undergoing CABG since March 1977 were reviewed. Patients requiring tracheostomy and those developing mediastinitis were identified. Mediastinitis diagnosis required positive culture of mediastinal tissue or fluid. RESULTS: After CABG, 88 patients had tracheostomy performed (1.45%). Seven patients receiving tracheostomy after developing mediastinitis were excluded. Of the remaining 81 patients, 7 developed mediastinitis (8.6%) compared with 44 of 5,969 (0.7%) who did not require tracheostomy (p < 0.001). Mortality in tracheostomy patients was 24.7% (20 of 81) compared with 5.2% in patients not requiring tracheostomy (316 of 5,969; p < 0.001). Patients not developing mediastinitis had tracheostomy placement an average of 25 days after CABG compared with 18.7 days for those developing mediastinitis (p = 0.141). CONCLUSIONS: Tracheostomy after CABG is associated with increased incidence of mediastinitis and mortality. In this review, the time interval between CABG and tracheostomy was not predictive of mediastinitis. A larger sample size would be required to be confident that there is no correlation.

Laboratory confirmation of clinical heart allograft preservation variability.

BACKGROUND: Previously, we reported survival differences from the national heart transplant registry favoring centers that used intracellular organ preservation solutions. To eliminate center selection bias, we tested some of these solutions in a biventricular working rat heart model to determine their relative efficacy. METHODS: Using 103 Sprague-Dawley rat hearts perfused with modified Krebs-Henseleit buffer, both ventricles functioned with adjustable independent preload and afterload and their pressure-length loops generated load-insensitive measurements of cardiac performance. After 15 minutes of stable function, each heart sustained 180 minutes of cold (4 degrees C) ischemia after a 5-minute perfusion by University of Missouri (UMC), Plegisol, Collins, University of Wisconsin, Custodiol, or Roe solutions. Eighty-two hearts were reperfused and the remainder were used for ATP analyses. RESULTS: Although the extracellular solution Plegisol showed good recovery of traditional hemodynamic values, including developed pressure and cardiac output, intracellular solutions like Roe had superior preservation of load-insensitive indices such as preload recruitable stroke work: Roe (intracellular) 103%+/-13%; Custodiol (intracellular) 96%+/-9%; UW (intracellular) 69%+/-12%; Collins (intracellular) 68%+/-9%; Plegisol (extracellular) 68%+/-7%; and University of Missouri (extracellular) 56%+/-10% (p = 0.04). Furthermore, recovery with intracellular solutions tended to be gradual but more progressive after ischemia in contrast to an early plateau shown by extracellular (p < 0.001). Right ventricular recovery and ATP measurements were similar between groups. CONCLUSIONS: These data support the superiority of certain intracellular preservation solutions and provide evidence that optimal heart organ protection may be difficult to judge clinically using hemodynamic values routinely available to the heart transplant surgeon. Care should be taken to verify the performance of some solutions used in heart organ transplantation.

Centrifugal pumps: description of devices and surgical techniques.

BACKGROUND: Because of simplicity of application, universal access, and low cost, centrifugal pumps are commonly used for short-term mechanical cardiac assist. Indications and techniques for application of this technology continue to evolve. METHODS: The clinical experience with 151 patients undergoing centrifugal mechanical cardiac assist at the University of Missouri-Columbia has been reviewed. We have compared commonly available centrifugal pumping systems in vitro and in vivo for characteristics that might distinguish them. RESULTS: Centrifugal pumps have been found to be well suited for use in surgery on the thoracic aorta, for extracorporeal membrane oxygenation and for postcardiotomy cardiac mechanical assist. Complications associated with centrifugal mechanical assist are predictable and common but potentially can be reduced by improved surgical techniques and anticoagulation strategies. In vitro and in vivo experimentation with available centrifugal pumps reveals nuances characteristic of each of the devices. CONCLUSIONS: All centrifugal pumps presently available are less destructive to blood cellular elements compared with roller pumps. With familiarity, all can function satisfactorily for short-term mechanical assist with no compelling evidence that favors any particular centrifugal pump system clinically available. Centrifugal pumps are ideally suited for left heart bypass during surgery on a thoracic aorta and for short-term application as may be required for postcardiotomy mechanical assist. Centrifugal pump technology should be part of the armamentarium of all cardiothoracic surgeons.

Minimally invasive lobectomy directed toward frail and high-risk patients: a case-control study.

BACKGROUND: To compare minimally invasive video-assisted thoracic surgery (VATS) with thoracotomy, cases were matched from a pool of pulmonary lobectomies performed by one surgeon who offered VATS for patients with unfavorable risk factors. METHODS: A thoracotomy case was paired to each of 19 VATS cases by age, sex, lobe, side, and forced expiratory volume in 1 second. Eleven VATS and 5 thoracotomy patients with severe activity impairments or reduced forced expiratory volume in 1 second (< 1.5 L or 50% predicted) were classified as higher risk than the others. RESULTS: Despite more high-risk cases, VATS yielded shorter hospitalizations (5.3+/-3.7 versus 12.2+/-11.1 days, p = 0.02), chest tube durations (4.0+/-2.8 versus 8.3+/-8.9 days, p = 0.06), and earlier returns to full preoperative activities (2.2+/-1.0 versus 3.6+/-1.0 months, p < 0.01). The VATS operations had no intraoperative complications and lasted 229+/-59 minutes. Pain 3 weeks later was dramatically better for the VATS group (none or mild, 63% versus 6%; severe, 6% versus 63%; p < 0.01). Six complications or deaths occurred in each group and were related to forced expiratory volume in 1 second, steroid usage, age, active smoking, and upper lobe resection (p < 0.01). Three VATS deaths occurred only in elderly, performance status 3 patients, with two caused by gastrointestinal-related problems masked by steroid use. CONCLUSIONS: A VATS lobectomy is less painful and may offer faster recovery for the frail or high-risk patient. Further study, particularly of its safety in severely activity-impaired patients, is warranted.

The heartmate left ventricular assist system: first successful implantation in Missouri.

We report a case of the first successful implantation of the HeartMate left ventricular assist system as a bridge to heart transplant in the state of Missouri. Indications, technique of insertion, patient selection, outcomes and future applications are discussed.

Multicenter VATS experience with mediastinal tumors.

BACKGROUND: The use of video-assisted thoracic surgery for diagnosis and treatment of mediastinal tumors in a multiinstitution patient population is not well understood. METHODS: We studied 48 cases from Cancer and Leukemia Group B thoracic surgeons. Of 21 men and 27 women, aged 41 +/- 16 years, 22 patients were asymptomatic. In the others, 92% of tumor-related symptoms improved or resolved after treatment. Five tumors involved the anterior compartment, 19 the middle, and 24 the posterior compartment. Diagnoses were typical for each compartment but also included uncommon problems such as superior vena cava hemangioma and a histoplasmosis cyst causing hoarseness. Of the lesions, a biopsy of 12 was done without excision and the rest were excised completely. Fifteen were cystic and 10 were malignant (8 biopsy only). Maximal dimensions were 5.2 +/- 3.3 cm. RESULTS: Operations were briefer for 24 posterior (93 +/- 41 min) than 5 anterior (195 +/- 46 min, p < 0.01) or 19 middle mediastinal tumors (170 +/- 78 min, p < 0.01). Although 96% had vital mediastinal relations, only six open conversions were performed because of bleeding (n = 3), large size, impaired exposure, or rib attachments, and no patient had morbidity beyond that expected for the thoracotomy. Postoperative stay was shorter for the nonconversion group (3.2 +/- 2.8 versus 5.5 +/- 2.1 days, p = 0.05), as was chest tube duration (1.7 +/- 1.4 days versus 3.2 +/- 1.9 days, p = 0.03). There were no postoperative deaths or major complications, but 7 patients had minor complications. During a mean of 20 months of surveillance (range, 1 to 52 months), one cyst recurred (asymptomatic) as did one sarcoma that was excised. CONCLUSIONS: Video-assisted thoracic surgery is a safe technique for benign mediastinal tumors, typically those in the middle and posterior mediastinum.

Thoracoscopic sympathectomy: the U.S. experience.

OBJECTIVE: 48 patients underwent TSSYM. Charts of patients undergoing thoracoscopy were reviewed to assess the safety and efficacy of thoracoscopic sympathectomy (TSSYM). DESIGN: A retrospective review was undertaken at four United States medical centers. RESULTS: TSSYM was performed for reflex sympathetic dystrophy in 27 patients, hyperhydrosis palmaris in 15 patients, and Raynaud's upper extremity ischemia and splanchnic pain in 2 patients each. Anesthesia with one lung ventilation was used. 2.9 ports were used per patient and 0.8 chest tubes were placed per patient. All patients underwent resection of the sympathetic chain, usually with a clip along the bottom of the resected chain. Laser, electro-ablation and electroresection were not used by any of the surgeons in his series. The mean length of hospital stay was 1.8 days. CONCLUSIONS: TSSYM is a safe and effective technique for treatment of a variety of thoracic disorders.

Incidence and predictors of supraventricular dysrhythmias after pulmonary resection.

BACKGROUND: Patients undergoing pulmonary resection were evaluated prospectively in an effort to determine the incidence of and predictors for the development of postoperative supraventricular dysrhythmias. Specifically, we wished to test the hypothesis that the incidence of postoperative supraventricular dysrhythmias is dependent on the magnitude of pulmonary resection. METHODS: One hundred sixteen patients undergoing pulmonary resection had continuous Holter monitoring preoperatively, the day of operation, and the second postoperative day, as well as continuous cardiac monitoring throughout hospitalization. Holter interpretation was blinded to extent of resection. RESULTS: Twenty-six patients underwent pneumonectomy, 7 bilobectomy, 47 lobectomy, and 36 wedge resection. Twenty-six patients (22.4%) had supraventricular dysrhythmias, all atrial fibrillation +/- flutter. The incidence of atrial fibrillation with pneumonectomy, bilobectomy, single lobectomy, and wedge resection was 46.1%, 14.3%, 17.0%, and 13.8%, respectively (p < 0.005 pneumonectomy versus others). Overall, 31% of patients having pneumonectomy required pharmacologic therapy for dysrhythmia compared with 16% of patients having lesser resections, (p = 0.03). The peak incidence of onset of atrial fibrillation occurred on postoperative days 2 and 3 and lasted for less than 1 to 7 days, average 2.5 days. The average age of patients with dysrhythmias (64 years) was greater than those without (58 years) (p = 0.039). Thirty pre- and postoperative variables tested were not found to be significant predictors for development of postoperative atrial fibrillation. CONCLUSIONS: Atrial fibrillation occurs commonly after pulmonary resections but is not predictable. Development of atrial fibrillation is not dependent on the magnitude of pulmonary resection but is associated with the procedure pneumonectomy for reasons not elucidated.

In vivo left ventricular assist induced coagulation derangements. Comparison of Sarns-3M and St. Jude Medical circuits.

An in vitro comparison of centrifugal pumping systems manufactured by Sarns-3M and St. Jude Medical revealed a difference in blood cell derangement. The purpose of this study was to compare in vivo the effects of 96 hr of left ventricular assist (LVA) on indexes of coagulopathy, hemolysis, and complement activation. Two groups of calves (each: n = 5) were instrumented with identical left atrial to thoracic aorta centrifugal pumping circuits using either Sarns-3M or St. Jude centrifugal pumps. Laboratory evaluations were performed pre-assist and at 1, 4, 24, 48, 72, and 96 hr during LVA. Platelet counts dropped significantly by 24 hr (Sarns-3M: 28%; St. Jude: 30%); no significant change in function was noted. Activated clotting time increased slightly (p > 0.05). Prothrombin time increased at 4 and 24 hr of LVA, returning to baseline by 96 hr (p < 0.05). Activated partial thromboplastin time increased with the St. Jude device from 24 to 96 hr on LVA (p < 0.05); the increase with the Sarns-3M device never reached significance. No significant changes in lactate dehydrogenase or plasma free hemoglobin were detected. Complement fraction C5a rose by 1 hr of LVA (p < 0.05), peaking at 4 hr and returning to baseline by 96 hr with both pumps. No significant difference was detected between pump groups for any of the parameters. It was concluded that 1) 96 hr Sarns-3M and St. Jude LVA caused coagulation derangement in calves, 2) neither pump demonstrated an advantage regarding coagulation and complement parameters, 3) hemolysis observed with the Sarns-3M pump in vitro was not evidenced in vivo, and 4) in vitro evidenced centrifugal pump differences may not be realized in vivo.

Feasibility of mathematical models to predict success in video-assisted thoracic surgery lung nodule excision.

BACKGROUND: Pulmonary nodules are occasionally difficult to excise using video-assisted thoracic surgery (VATS). METHODS: To predict operative success, mathematical models using preoperative computerized tomography (CT) measurements were tested in 50 consecutive patients who underwent attempted or successful thoracoscopic lung biopsy. Unrelated technical problems resulted in the exclusion of 3 patients. RESULTS: No differences were noted with respect to lobar location, thoracic dimensions, gender, presence of chronic obstructive pulmonary disease, or nodule pathology. The expression S/(D + 1), where S = nodule size (cm) and D = distance (cm) to the nearest visceral pleura, yielded significantly higher values for visible nodules (P < 0.001). Resectable nodules had a higher score using the expression 1/(S + D + 1), (P < 0.001). Simple cases (n = 19) were defined as those in which nodules were both visible and resectable with very basic VATS techniques. All others (n = 28) were considered complex. The derived expression for Simplicity [1/(S(D + 1))] yielded significantly higher values for simple cases (0.8 +/- 0.3 vs. 0.3 +/- 0.2 cm(-2), P < 0.001) and all simple cases had a score > or = 0.4. Logistic regression analysis showed that the formulas for resectability and simplicity were significant independent predictors for resectability and simplicity. CONCLUSIONS: Equations based on objective CT measurements may be useful for planning VATS nodulectomy or studying the outcome of these minimally invasive operations.

Load-Insensitive Measurements from an Isolated Perfused Biventricular Working Rat Heart.

To determine whether a rat heart model can provide load-insensitive measurements of cardiac function, a recently developed biventricular perfused preparation was tested. Using 29 Sprague-Dawley rat hearts perfused with modified Krebs-Henseleit buffer, ventricles functioned simultaneously with adjustable independent preload (venous reservoirs) and afterload (compliance chambers). Ultrasonic crystal pairs provided continuous left (LV) and right ventricular (RV) short-axis dimensions. LV and RV pressure-length loops (loop area = work) were generated from paired intraventricular pressure and short-axis dimensions. Load-insensitive measurements were obtained from the slopes (elastance) and x-intercepts (L(0)) of regression lines generated from the end-systolic coordinates of these pressure-length loops over ranges of RV and LV preloads. Measurements were made after 15 min of stable function and after 20 min of warm (37 degrees C) ischemia. During perturbations in LV afterload, there were linear changes in dP/dt, but loop work remained relatively unchanged. RV dP/dt and work varied little with physiologic ranges of afterload. Increased RV afterload had little effect on LV function. Ischemia affected LV function more than RV function using these measurements. Elastance, however, increased after ischemia with diastolic 'creep' (increased L(0)) for both ventricles. Load-insensitive and other sophisticated hemodynamic measurements are possible with this new preparation. Copyright 1997 S. Karger AG, Basel

Organ preservation solutions in heart transplantation--patterns of usage and related survival.

Despite experimental advantages for certain heart preservation solutions (HPS), their clinical popularity and related survival are uncertain. We surveyed all active UNOS heart transplant centers to determine their HPS. HPS survival benefits were tested using the UNOS heart transplant registry. Centers used from 1 to 3 types of 167 solutions. Of these formulations, 55.1% were commonly cited solutions. The other (custom) mixtures differed from those usually reported. All solutions were classified as intracellular (I, [Na++] < 70 mEq/L) or extracellular (E, [Na++] > or = 70 mEq/L). Significant variations in solution usage were observed among major regions of U.S. transplant activity (Northeast [NE], Southeast [SE], and West [W], P < 0.001). For example, 62.5% of University of Wisconsin (UW) and 49.3% of "Other" usage occurred in the NE; 75% of Roe and 100% of Collins usage occurred in the SE; and 100% of Krebs and 46% of Stanford usage occurred in the W. Logistic regression analyses of 9401 patients who underwent transplantation from 10/87 to 12/92 showed a reduction in the adjusted one month mortality odds ratio for grafts preserved with I rather than E solutions (0.85, P < 0.05). Compared with the most commonly used solution, Plegisol (20.1% of cases), the following adjusted odds ratios for one-month mortality were observed: UW, 1.09 (ns); Stanford, 0.80 (P < 0.10); Roe, 0.36 (P < 0.001); Collins, 0.82 (ns); Krebs, 0.14 (P < 0.01). Using the same one month comparison with Plegisol, 16.8% of grafts that received Custom-I solutions also fared better (0.75, P < 0.05) than the 21.4% that had Custom-E mixtures (0.91, ns). HPS usage varies greatly and there are regional preferences. There may be early survival benefits for certain intracellular HPS--however, further study is warranted to explore such relationships.

Lung carcinoma-M0. Patterns and results of radiotherapy of all patients referred to one department.

All patients with M0 carcinoma of the lung regardless of the histology, exclusive of Pancoast tumors referred to the same radiation oncology team from 1988 to 1992 were identified. They were 101 patients; 16 of whom were postoperative. To determine the patterns of radiation therapy and results, these cases were analyzed according to the radiation dose and volume irradiated. Fifteen patients had no or futile dose of radiation because of poor general condition. No prophylactic radiotherapy was intentionally given to the supraclavicular area. Relief of symptoms occurred in 87% of symptomatic, evaluable patients. Distant metastases developed in 20% of patients. There were no local recurrences in the nonirradiated supraclavicular or prophylactically irradiated mediastinal areas. Increasing the dose to the primary tumor from 6,000-6,500 to 6,600-7,000 cGy (180-200 cGy/fraction) was tried in a small number of patients with encouraging results.

Post-transcriptional regulation of extracellular matrix metalloproteinase in human heart end-stage failure secondary to ischemic cardiomyopathy.

Human heart matrix metalloproteinases (MMP) are present in the latent form and activated in the failing heart. To examine whether the MMP activation was due to gene and/or post-translational modification, we analysed tissue from 10 explanted hearts due to coronary heart disease (CHD) and five normal left atrial tissue from donor hearts. Based on in situ immunolabeling MMP-1, tissue inhibitor of metalloproteinase (TIMP-1) and collagen were co-localized in the interstitial tissue. Based on sandwich ELISA, TIMP-1 and MMP-1 levels were 37 +/- 8 ng/mg and 9 +/- 2 ng/mg in normal tissue (P < 0.01) and 12 +/- 5 ng/mg and 75 +/- 11 ng/mg in the infarcted tissue (P < 0.01), respectively. These levels suggest repression of TIMP-1 during myocardial infarction. Northern blot analysis indicated that the mRNAs for both MMP-1 and TIMP-1 were increased three-to four-fold in the infarcted tissue as compared to the normal tissue, suggesting upregulation of MMP and TIMP gene transcription following infarction. Based on in situ tissue overlay zymography, the generalized activation of MMP was observed in the interstitium of the infarcted heart. Zymographic and immunoblot analysis demonstrated the presence of one band at 66 kDa (MMP-2) in the normal tissue and several bands at 92 (MMP-9), 66 (MMP-2) and 54 kDa (MMP-1) in the infarcted heart. Incubation of the zymographic gel with metal chelator (phenanthroline) abolished bands at 92 kDa and 54 kDa but phenanthroline did not abolish the lytic band at 66 kDa. The 66 kDa band was completely abolished in the presence of phenanthroline and phenyl methyl sulfonyl fluoride (PMSF). 2D-zymographic analysis suggested that the lytic band at 66 kDa was a mixture of two neutral proteinases with different isoelectric point. Plasminogen/gelatin zymographic analysis of infarcted tissue extract indicated that the band at 66 kDa was plasmin generated due to increased expression of tissue plasminogen activator (tPA) activity. In relation to increased expression of gelatinase in the infarcted tissue, our data suggest that gelatinase B (92 kDa) is induced in diseased heart. The results suggest that tPA converts plasminogen to plasmin which, in turn, activates MMPs and inactivates TIMP-1 post-translationally following ischemic cardiomyopathy.

Subchronic use of the St. Jude centrifugal pump as a mechanical assist device in calves.

The purpose of this experiment was to study the effects of the St. Jude Lifestream centrifugal pump on hemodynamic and hematologic parameters and the incidence of postmortem findings in a subchronic ex vivo left ventricular assist animal model. Five calves were implanted with the pump as a left ventricular assist device (left atrial to thoracic aorta bypass) and studied for 96 h of continuous pumping under identical conditions. Heparin (100 IU/kg) was administered only in the initial saline pump prime. Throughout the protocol, mean arterial and central venous pressures averaged 102.1 +/- 4.6 and 3.4 +/- 2.2 mm Hg, respectively. Pump flow was 47.8 +/- 8.4 ml/kg/min at a mean pump speed of 1,676.3 +/- 106.1 rpm. No clinical abnormalities or mechanical malfunctions attributable to the pump were detected during the 96 h of continuous pumping for each calf. Mean plasma-free hemoglobin after 96 h was 3.9 +/- 3.7 mumol/L (p = 0.337 compared to baseline). At post mortem, renal infarctions were detected in 1 calf. No other pump-associated lesions were detected in any of the other calves. We have concluded that the St. Jude Lifestream centrifugal pump functions reliably during 96 h of continuous left heart bypass in a calf model.

Subchronic centrifugal mechanical assist in an unheparinized calf model.

The purpose of this study was to determine whether the major centrifugal pumps currently in use in the United States (Medtronic, BioMedicus BioPump and Carmeda-coated BioPump, Sarns 3M centrifugal pump, and St. Jude Medical Lifestream) could function as left mechanical assist devices in the subchronic (72 h) unheparinized calf model. Calves were instrumented for left atrial to aorta ex vivo assist, and the pump flow was set at 3.5 +/- 0.4 L/min. Two calves (Sarns 3M and St. Jude) survived 72 h of pumping without clinical complications. The other 2 calves died at 62 and 66 h (Medtronic BioPump and Carmeda-coated BioPump, respectively); both had pelvic limb paralysis. The seal of the Sarns 3M pump head ruptured after approximately 36 h of pumping and required replacement. On postmortem examination, pump-associated thromboembolic lesions were detected in 3 of the 4 calves in one or more of the following organs: kidneys, pancreas, abomasum, duodenum, ileum, spleen, and lumbar spinal cord. The calf with the Sarns 3M pump had no discernable lesions. Because of the clinical abnormalities and postmortem lesions in the unheparinized calf model, it was suggested that anticoagulation is necessary for conducting centrifugal mechanical assist studies in calves using presently available technology.