Robert M. Bojar

Postoperative cardiac tamponade in the modern surgical era

BACKGROUNDnPericardial effusions resulting in cardiac tamponade (CT) are uncommon after open heart surgery (OHS) and are associated with significant morbidity and mortality. Characteristics and outcomes of patients who develop postoperative CT are poorly defined. Our objective was to further analyze the population at risk for developing postoperative CT, identify potential perioperative and surgical risk factors, and evaluate the impact of CT on patient outcomes.nnnMETHODSnA retrospective analysis of 4,561 consecutive patients undergoing OHS at our institution was performed. Patients with clinical suspicion of pericardial effusion following surgery were evaluated by transthoracic or transesophageal echocardiography, and clinical parameters were analyzed.nnnRESULTSnForty-eight (1%) of the 4,561 patients were found to have echocardiographic evidence of a moderate or large pericardial effusion, of whom 36 (74%) had evidence of CT. The mean age of the patients with CT was 61 years. Coronary artery bypass grafting (CABG) had been performed in 24% of these patients, valve +/- CABG in 73%, and other OHS procedures in 3%. The incidence of CT following CABG alone was 0.2%, whereas it was 0.6% after valve +/- CABG. Females had a higher risk for developing CT, and this occurred earlier in the postoperative period when compared with men. Aspirin, heparin, or warfarin were given to 84% of patients within 3 days of surgery. Mean time to diagnosis of CT was 10 +/- 1 days after OHS. Prior to diagnosis of CT, the maximum international normalized ratio (INR) and partial thromboplastin time (PTT) were 2.7 +/- 0.3 and 68 +/- 5 seconds, respectively. Forty-nine percent of pericardial effusions were posterior and 46% were circumferential; one-third of the effusions were considered large by echocardiography. There was one in-hospital cardiovascular death.nnnCONCLUSIONSnCT after OHS is more common following valve surgery than CABG alone and may be related to the preoperative use of anticoagulants. Females appear to be at higher risk for developing early postoperative CT. When diagnosed and treated promptly, postoperative CT should not significantly increase mortality.

Clinical benefits of endoscopic vein harvesting in patients with risk factors for saphenectomy wound infections undergoing coronary artery bypass grafting

OBJECTIVEnThe influence of endoscopic harvesting techniques on the prevalence of leg-wound complications after coronary artery bypass grafting remains to be defined for patients at high risk for the development of wound infections.nnnMETHODSnAmong 1473 patients undergoing coronary artery bypass grafting who had the saphenous vein harvested by either a continuous incision or skip incisions leaving intact skin bridges, we determined the prevalence of wound infections to be 9.6%. The following variables were entered into logistic regression analysis to identify significant risk factors that might be predictive of wound infection: diabetes, peripheral vascular disease, obesity, renal failure, steroid use, age, sex, and type of closure. We then prospectively randomized 132 patients found to be at high risk of wound infection to either endoscopic vein harvesting or a continuous open incision.nnnRESULTSnUnivariate analysis showed female sex (P =.04), diabetes (P <.001), and obesity (P <.001) to be predictors of wound infection. In a multivariate model diabetes (P =.02) and obesity (P =.001) were independent predictors. In patients at high risk, the prevalence of wound infection was 4.5% for the endoscopic group versus 20% for the open group (P =.01). Vein procurement time was greater in the endoscopic group (65 minutes vs 32 minutes, P <.001), as was the number of vein repairs required (2.5 vs 0.6, P <.001).nnnCONCLUSIONnThe use of endoscopic vein harvesting decreases the prevalence of postoperative leg-wound infections in high-risk patients with diabetes and obesity. Whether this translates into an economic benefit that justifies the additional cost of that technology requires further analysis.

Simultaneous carotid endarterectomy and coronary bypass: Perioperative risk and long-term survival

PURPOSEnThe purpose of this article is to examine the outcome of simultaneous coronary bypass-carotid endarterectomy (CABG-CEA) and to compare it with the outcome of endarterectomy alone (CEA alone) in patients at high cardiac risk.nnnMETHODSnA retrospective review of the records and follow-up data for 100 consecutive patients who had undergone CABG-CEA and were at high risk and 114 patients who had undergone CEA, had overt coronary artery disease (angina, previous infarct, or ischemic electrocardiographic abnormalities), but had not undergone CABG was carried out.nnnRESULTSnOur CABG-CEA group had a high incidence of symptomatic carotid disease (57%) and contralateral occlusion (28%) when compared with patients in other reports. Patients in the CABG-CEA group were older (67.9 +/- 8.3 years vs 63.6 +/- 15.7 years, p = 0.01) and more often smokers (81% vs 52.6%, p = 0.01) than patients in the CEA alone group. Perioperative mortality was 8% for the CEA-CABG group and for 1.8% for the CEA alone group (p = 0.035). Perioperative stroke morbidity was 9% for the CEA-CABG group and 2.6% for the CEA alone group (p = 0.05). Life table survival at 1,3, and 5 years was 90%, 82%, and 73% versus 96%, 84%, and 76% for the CABG-CEA and CEA alone groups, respectively (p = 0.30).nnnCONCLUSIONSnSelection criteria for CABG-CEA greatly influence perioperative risk. Despite the greater age and more advanced coronary artery disease in the CABG-CEA group, long-term outcome differences are accounted for entirely by differences in perioperative morbidity and mortality. Prospective trials of strategies such as staged CEA and CABG to reduce perioperative risk are needed.

Efficacy of Retrograde Coronary Sinus Cardioplegia in Patients Undergoing Myocardial Revascularization: A Prospective Randomized Trial

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

Intravascular ultrasound imaging in acute aortic dissection

OBJECTIVESnThis study was performed to determine the potential of intravascular ultrasound in the detection and delineation of aortic dissection.nnnBACKGROUNDnIntravascular ultrasound is a new technique capable of displaying real-time cross-sectional images of arterial vasculature. Its clinical use has been explored mostly in coronary and peripheral arterial circulation.nnnMETHODSnIntravascular ultrasound imaging of the aorta was performed using a 20-MHz ultrasound catheter in 28 patients with suspected aortic dissection. All patients underwent contrast angiography; 7 had computed tomography; and 22 had transesophageal echocardiography.nnnRESULTSnImaging of the aorta from the root level to its bifurcation was performed in all patients in an average of 10 min. No complications occurred. Dissection was present in 23 patients and absent in 5. In the patients without dissection, intravascular ultrasound revealed normal aortic anatomy. In all 23 patients with dissection, intravascular ultrasound demonstrated the intimal flap and true and false lumena. The longitudinal and circumferential extent of aortic dissection, contents of the false lumen, involvement of branch vessels and the presence of intramural hematoma in the aortic wall could also be identified. In cases where aortography could not define the distal extent of the dissection, intravascular ultrasound did.nnnCONCLUSIONSnOur experience in this series of patients with aortic dissection indicates that intravascular ultrasound could be valuable in the identification and categorization of aortic dissection and in the description of associated pathologic changes that may be clinically important. It can be performed rapidly and safely and could serve as an alternative or adjunct diagnostic procedure in patients with aortic dissection.

Clinical and hemodynamic performance of the 19-mm Carpentier-Edwards porcine bioprosthesis

Because of concerns about the hemodynamic performance of 19-mm porcine valves, we retrospectively reviewed the clinical results and echocardiographic studies of 52 consecutive patients who received a 19-mm Carpentier-Edwards porcine bioprosthesis (model 2625) for aortic valve replacement from 1986 through 1991. Nearly 87% of the patients were women, the mean age was 69 years, and the mean body surface area was 1.63 +/- 0.27 m2. Seventy-three percent of the patients had pure aortic stenosis, 96% were in New York Heart Association classes III and IV, and 56% underwent urgent or emergent operation. Overall hospital mortality was 7.7% with a late mortality of 8.3% at a mean follow-up of 25 +/- 18 months. No patient experienced a valve-related complication, and 95% of surviving patients were in New York Heart Association classes I and II. Two-dimensional and Doppler echocardiography performed during the first postoperative week revealed a maximal instantaneous gradient of 44.7 +/- 13.0 mm Hg. In 43 patients for whom additional data were available, the mean gradient was 26.4 +/- 8.2 mm Hg with an effective orifice area of 0.85 +/- 0.18 cm2. This study defines the normal range of postoperative gradients across the 19-mm Carpentier-Edwards porcine valve and demonstrates that patients receiving this valve can achieve significant clinical improvement despite the presence of high transvalvular gradients measured by echocardiography.

Surgical treatment of systemic atheroembolism from the thoracic aorta

BACKGROUNDnSurgical procedures performed exclusively for atheroembolic events arising from the thoracic aorta rarely have been reported. Presented here are 2 patients who underwent successful operation for these problems.nnnMETHODSnThe clinical presentation, diagnostic evaluation and surgical approach to 2 patients with different embolic sources in the thoracic aorta are presented. One patient had experienced three strokes and was noted by multiplane transesophageal echocardiography to have protruding atheromas with ulcerations in the transverse arch and origin of the brachiocephalic vessels. The transverse arch was replaced using hypothermic circulatory arrest with individual reimplantation of the brachiocephalic vessels. The second patient presented with blue toe syndrome from mobile atheromas in the mid-descending thoracic aorta defined by transesophageal echocardiography. A localized debridement was performed using simple aortic cross-clamping.nnnRESULTSnBoth patients had uneventful postoperative courses and had no further atheroembolic events.nnnCONCLUSIONSnWhen standard diagnostic modalities do not delineate an embolic source for either stroke or peripheral embolization, transesophageal echocardiography is recommended as an excellent means of identifying atheromas in the thoracic aorta that could be the source for emboli. Once these lesions are identified, a surgical procedure should be performed to prevent further embolization.

Visualization of Left Ventricular Pseudoaneurysm With Panoramic Transesophageal Echocardiography

The diagnosis and precise delineation of a pseudoaneurysm of the left ventricle have important implications regarding surgical planning and operative repair. A 68-year-old man was admitted to the hospital with the incidental finding of a large pseudoaneurysm of the left ventricle 6 months after a St. Jude mitral valve replacement performed for partial papillary muscle rupture after an acute myocardial infarction. Panoramic transesophageal echocardiography provided a full depiction of the left ventricle and the adjoining pseudoaneurysm, enhancing the preoperative evaluation of the extent of the defect. A successful repair was undertaken with a pericardial patch.

Use of Self-Adhesive External Defibrillator Pads for Complex Cardiac Surgical Procedures

We describe a useful technique for the management of life-threatening arrhythmias that occur during complex or reoperative cardiac surgical procedures when internal defibrillation cannot be achieved. Two self-adhesive external pads are attached to the patient before draping to enable the delivery of current for defibrillation or cardioversion without the need for removal of adhesive surgical drapes and the cumbersome use of external defibrillator paddles.

Methemoglobinemia from intravenous nitroglycerin: a word of caution

The dose of intravenously administered nitroglycerin (IV NTG) used to control ischemic chest pain usually is limited by hypotension from decreased preload. Herein we describe 2 patients who tolerated IV NTG without hemodynamic compromise but in whom severe impairment of blood oxygen content developed from methemoglobinemia noted during coronary bypass surgery. Methemoglobinemia must be suspected if chocolate-brown blood is encountered despite a normal arterial oxygen tension and calculated oxygen saturation. Before a methemoglobin level is available, the extent of hypoxemia can be determined by an oximetric oxygen saturation and therapy begun with intravenous administration of methylene blue. These case reports focus attention on the potential deleterious effects of undetected hypoxemia from methemoglobinemia in patients being stabilized with high-dose IV NTG for urgent cardiac surgery.