Michael A. Wait

Dobutamine stress echocardiography identifies hibernating myocardium and predicts recovery of left ventricular function after coronary revascularization.

BackgroundThe identification of hibernating myocardium is important in selecting patients who will benefit from coronary revascularization. This study was performed to determine whether dobutamine stress echocardiography (DSE) could identify hibernating myocardium and predict improvement in regional systolic wall thickening after revascularization. Methods and ResultsDSE was performed in 49 consecutive patients with multivessel coronary disease and depressed left ventricular function. Contractile reserve during DSE was defined by the presence of two criteria: (1) improved systolic wall thickening in at least two adjacent abnormal segments and (2) .20%o improvement in regional wall thickening score. Postoperative echocardiograms were evaluated for improved regional wall thickening in 25 patients at least 4 weeks after successful coronary revascularization. All studies were read in blinded fashion. Contractile reserve during DSE was present in 24 (49%o) of 49 patients. The presence or absence of contractile reserve on preoperative DSE predicted recovery of ventricular function in the 25 patients who underwent successful revascularization. Thus, 9 of 11 patients with contractile reserve had improved systolic wall thickening after revascularization (hibernating myocardium), whereas 12 of 14 patients without contractile reserve did not improve (P=.003). ConclusionDobutamine stress echocardiography provides a simple, cost-effective, and widely available method of identifying hibernating myocardium and predicting improvement in regional left ventricular wall thickening after coronary revascularization. This technique may be clinically valuable in the selection of patients for coronary revascularization.

Early Evacuation of Traumatic Retained Hemothoraces Using Thoracoscopy: A Prospective, Randomized Trial

BACKGROUND Failure to adequately evacuate blood from the pleural space after trauma may result in extended hospitalization and complications such as empyema. METHODS Patients with retained hemothoraces were prospectively randomized to either a second tube thoracostomy (group 1, n = 24) or video-assisted thoracoscopy (VATS) (group 2, n = 15). Group 1 patients in whom additional tube drainage failed were subsequently randomized to either VATS or thoracotomy. Study end points included duration and costs of hospitalization. RESULTS During a 4-year period, 39 patients were entered into the study. Patients in group 2 had shorter duration of tube drainage (2.53 +/- 1.36 versus 4.50 +/- 2.83 days, mean +/- standard deviation; p < 0.02), shorter hospital stay after the procedure (3.60 +/- 1.64 versus 7.21 +/- 5.30 days; p < 0.02), and shorter total hospital stay (5.40 +/- 2.16 versus 8.13 +/- 4.62 days; p < 0.02). Hospital costs were also less in this group (

Evaluation of video-assisted thoracoscopic surgery in the diagnosis of diaphragmatic injuries

7,689 +/- 3,278 versus

Indications for using video-assisted thoracoscopic surgery to diagnose diaphragmatic injuries after penetrating chest trauma

13,273 +/- 8,158; p < 0.02). There was no mortality in either group. No group 2 patient required conversion to thoracotomy. In 10 group 1 patients additional tube placement failed, and this subset was randomized to VATS (n = 5) or thoracotomy (n = 5). No significant difference in clinical outcome was found between these subgroups. CONCLUSIONS In many patients treated only with additional tube drainage (group 1), this therapy fails, necessitating further intervention. Intent to treat with early VATS for retained hemothoraces decreases the duration of tube drainage, the length of hospital stay, and hospital cost. Early intervention with VATS may be a more efficient and economical strategy for managing retained hemothoraces after trauma.

Changing clinical spectrum of spontaneous pneumothorax

BACKGROUND Injury to the diaphragm from penetrating or blunt thoracoabdominal trauma is notoriously difficult to diagnose. Chest radiography, computed tomography scan, contrast studies, diagnostic peritoneal lavage, and laparoscopy are inadequate; thus, celiotomy is commonly performed in patients with suspected diaphragmatic injury. We compared the diagnostic accuracy of video-assisted thoracoscopic surgery (VATS) with that of exploratory celiotomy in the evaluation of diaphragmatic and thoracoabdominal injury. PATIENTS AND METHODS Hemodynamically stable patients admitted to a level I trauma center with blunt or penetrating injury to the lower chest or abdomen underwent VATS and subsequent celiotomy under the same general anesthetic. Intraoperative thoracoscopic findings were blinded to the abdominal surgeons. RESULTS Twenty-six patients were enrolled in the study over a 12-month period. Diaphragmatic injuries were identified in 8 patients (31%). Videothoracoscopy identified all eight injuries in these patients. Six of the 8 patients (75%) with diaphragmatic injuries sustained associated injury to intrathoracic or intra-abdominal organs. There was no mortality and no procedure-related morbidity. There were no missed injuries in patients who underwent VATS. CONCLUSIONS Video-assisted thoracoscopy is a safe, expeditious, and accurate method of evaluating the diaphragm in injured patients, and is comparable in diagnostic accuracy to exploratory celiotomy.

Perfusion Preservation versus Static Preservation for Cardiac Transplantation: Effects on Myocardial Function and Metabolism

BACKGROUND Video-assisted thoracoscopic surgery (VATS) has been shown to be an accurate method for identifying diaphragmatic injuries (DIs). The purpose of this investigation was to establish specific indications for the use of VATS after penetrating chest trauma. METHODS A retrospective review of all patients undergoing VATS after penetrating chest trauma at a level 1 trauma center over an 8-year period was performed. Logistic regression was used in an attempt to identify independent predictors of DI. RESULTS One hundred seventy-one patients underwent VATS assessment of a hemidiaphragm, and 60 patients (35%) were found to have a DI. Five independent risk factors for DI were identified from analyzing the patient records: abnormal chest radiograph, associated intraabdominal injuries, high-velocity mechanism of injury, entrance wound inferior to the nipple line or scapula, and right-sided entrance wound. CONCLUSIONS In the largest published series of patients undergoing VATS to exclude a DI, this review identifies five independent predictors of DI after penetrating chest trauma. A diagnostic algorithm incorporating these five factors was designed with the goal of reducing the number of unrecognized DIs after penetrating chest trauma by using VATS for patients at greatest risk for such injuries.

Assessment of aortic regurgitation by transesophageal color Doppler imaging of the Vena contracta : Validation against an intraoperative aortic flow probe

The epidemiology and etiology of spontaneous pneumothorax (SP) are shifting away from the predominance of subpleural bleb disease as emphasized by most reports since that of Kjaergaard (Sweden, 1932). We conducted a retrospective review of all patients admitted to a large urban hospital with the diagnosis of SP over the past 8 years. Of 120 patients, 32 had the acquired immunodeficiency syndrome (AIDS) (group 1, 26.6%), 43 patients had classic subpleural bleb disease or chronic obstructive pulmonary disease with blebs (group 2, 35.8%), and 45 patients had nonbleb disease exclusive of AIDS (group 3, 37.5%). These three groups were studied with respect to primary success rates with differing modalities of therapy. Bilateral SP occurred in 34% of group 1 patients, 2% of group 2 patients, and 11% of group 3 patients. The in-hospital mortality was 34% in group 1 compared with 2% in group 2 and 4% in group 3. Thirty-four percent of group 1 patients had recurrent SP compared with 16% of group 2 patients and 8% of group 3 patients. This report describes the changing etiology and epidemiology of SP in a large urban hospital from 1983 to 1991 and represents the largest single-institution report of AIDS-related pneumothorax. Standardized therapy was shown to have predictably favorable results in patients with bleb disease and nonbleb disease exclusive of AIDS. SP in patients with AIDS was associated with a high mortality rate and primary treatment failure; small-bore catheters and nondrainage therapies have a very limited role in these patients.

Port site metastasis after laparoscopic staging of esophageal carcinoma

INTRODUCTION Continuous perfusion of donor hearts for transplantation has received increasing interest, but the effects on cellular metabolism, myocyte necrosis, and myocardial edema are not well defined. METHODS Pig hearts were instrumented with sonomicrometry crystals and left ventricular catheters. Left ventricular function was quantified by the pre-load-recruitable stroke work (PRSW) relationship. Hearts were arrested with Celsior solution with 5.5 mM 13C-glucose added, and removed and stored in cold solution (n = 4) or placed in a device providing continuous perfusion of this solution at 10 ml/100 g/min (n = 4). After 4 hours of storage, left atrial samples were frozen, extracted, and analyzed by magnetic resonance spectroscopy. Hearts were then transplanted into recipient pigs and reperfused for 6 hours, with function measured hourly. At the end of the experiment, left ventricular water content and serum creatine kinase-MB isoenzyme levels were measured. RESULTS Baseline left ventricular function was similar in both groups. During reperfusion, the volume-axis intercept of the PRSW relationship was significantly lower in hearts stored with continuous perfusion (p < 0.05), suggesting reduced contractile impairment. Magnetic resonance spectroscopy revealed a decrease in tissue lactate in hearts that received continuous perfusion. Serum creatine kinase-MB isoenzyme levels were higher hearts that had static storage (30.8 +/- 9.0 vs 13.2 +/- 2.7 ng/ml; p < 0.05). Left ventricular water content was similar in both groups (0.797 +/- 0.012 vs 0.796 +/- 0.014; p = 0.45). CONCLUSIONS Donor hearts sustain less functional impairment after storage with continuous perfusion. This technique reduces tissue lactate accumulation and myocardial necrosis without increasing myocardial edema and appears promising as a method to improve results of cardiac transplantation.

Duplex scanning of central vascular access sites in burn patients

OBJECTIVES This study was performed to validate the accuracy of color flow vena contracta (VC) measurements of aortic regurgitation (AR) severity by comparing them to simultaneous intraoperative flow probe measurements of regurgitant fraction (RgF) and regurgitant volume (RgV). BACKGROUND Color Doppler imaging of the vena contracta has emerged as a simple and reliable measure of the severity of valvular regurgitation. This study evaluated the accuracy of VC imaging of AR by transesophageal echocardiography (TEE). METHODS A transit-time flow probe was placed on the ascending aorta during cardiac surgery in 24 patients with AR. The flow probe was used to measure RgF and RgV simultaneously during VC imaging by TEE. Flow probe and VC imaging were interpreted separately and in blinded fashion. RESULTS A good correlation was found between VC width and RgF (r = 0.85) and RgV (r = 0.79). All six patients with VC width >6 mm had a RgF >0.50. All 18 patients with VC width <5 mm had a RgF <0.50. Vena contracta area also correlated well with both RgF (r = 0.81) and RgV (r = 0.84). All six patients with VC area >7.5 mm2 had a RgF >0.50, and all 18 patients with a VC area <7.5 mm2 had a RgF <0.50. In a subset of nine patients who underwent afterload manipulation to increase diastolic blood pressure, RgV increased significantly (34 +/- 26 ml to 41 +/- 27 ml, p = 0.042) while VC width remained unchanged (5.4 +/- 2.8 mm to 5.4 +/- 2.8 mm, p = 0.41). CONCLUSIONS Vena contracta imaging by TEE color flow mapping is an accurate marker of AR severity. Vena contracta width and VC area correlate well with RgF and RgV obtained by intraoperative flow probe. Vena contracta width appears to be less afterload-dependent than RgV.

Left hemiparesis from Atrial Myxoma emboli: Finalist, cardiology in review fellowship/residency clinical case contest

The case history of a patient who underwent laparoscopic staging of an esophageal carcinoma is presented. After neoadjuvant chemoradiation therapy a port site metastasis was found at esophagectomy. Possible etiologies, implications for the continued use of minimally invasive staging for esophageal carcinoma, and prevention of port site metastasis are discussed.