Robert R. Lazzara

Extracorporeal membrane oxygenation: Preliminary results in patients with postcardiotomy cardiogenic shock

Long-term survival at our institution for postcardiotomy cardiogenic shock patients supported with the BioPump is 36% (29/80 patients). A heparin-coated extracorporeal membrane oxygenator (ECMO), first introduced in 1991, may reduce organ injury associated with cardiopulmonary bypass. The device can be employed rapidly because it connects directly to the cardiopulmonary bypass cannula. In an effort to improve our results in the treatment of postcardiotomy cardiogenic shock, we used ECMO in 21 patients with this syndrome and accompanying complications. The patients were divided into three groups: group 1, ECMO after coronary artery bypass grafting; group 2, ECMO after mitral valve operation; and group 3, ECMO after open heart operation with prolonged cardiac arrest. Survival in group 1 was 80% with 12 of 14 patients discharged to home. All three deaths were caused by cardiac failure. Bleeding complications in this group were moderate. There was no evidence of disseminated intravascular coagulation, and levels of fibrin split products remained within the normal range. Postoperative complications included stroke (2), renal failure (1), mediastinitis (1), and prolonged respiratory failure (6). Mortality in group 2 was 100%. The major problem limiting recovery was left ventricular distention secondary to inadequate left ventricular decompression. Mortality in group 3 was 100%; all 4 died of brain death. Extracorporeal membrane oxygenation without left ventricular drainage clearly is not effective in patients undergoing mitral valve operations as it does not effectively decompress the left ventricle, but it was highly effective in treating postcardiotomy cardiogenic shock in our coronary artery bypass grafting patients. Extracorporeal membrane oxygenation also proved to be safe as the patient-related complications of stroke, renal failure, and mediastinitis were low. Our preliminary success with heparin-coated ECMO now needs to be confirmed by studies from other centers with larger groups of patients.

Minimally invasive surgical ablation of atrial fibrillation: the thoracoscopic box lesion approach.

BackgroundAtrial fibrillation is the most common cardiac rhythm disturbance and is associated with increased morbidity and mortality. It is often found in association with structural heart disease; however, lone atrial fibrillation is not uncommon. Potentially, these patients are ideal candidates for a minimally invasive thoracoscopic approach for the surgical treatment of atrial fibrillation.MethodsFrom August 2003 through February 2006, 100 drug-resistant symptomatic patients with lone atrial fibrillation underwent thoracoscopic off-pump closed-chest epicardial ablation using the FLEX 10 AFx Microwave Ablation System (Guidant, Indianapolis, IN, USA). There were 66 men (66.0%) and 34 women (34.0%), with a mean age of 60.9 ± 9.8 (range 37–81) years. Mean duration of atrial fibrillation was 72.4 ± 79.5 (range 6–480) months. Sixty-four patients (64.0% had paroxysmal, 11 (11.0%) had persistent and 25 (25.0%) had permanent atrial fibrillation.ResultsThere were no hospital deaths. Postoperative in-hospital complications were minimal. Mean postoperative length of stay was 3.4 ± 1.7 days. Cumulative follow-up was 2,106.3 (mean 23.1) patient months, with a maximum follow-up of 39.8 months. There were three late deaths (3.0%). In nine patients (9.0%), the thoracoscopic box lesion pulmonary vein isolation operation and subsequent electrophysiological intervention failed, and a Cox-Maze operation was performed. Follow-up was 100% complete, with 42.0% (37 of 88) patients in normal sinus rhythm. Two patients (2.3%) experienced a transient ischemic attack and two (2.3%) a cerebral vascular accident. Twenty-seven patients (30.7%) required electrophysiological intervention post procedure. Ten patients (11.4%) were on amiodarone and 48 (54.5%) were on coumadin at follow-up.ConclusionTotally thoracoscopic surgical ablation for the treatment of atrial fibrillation is technically feasible and presents minimal risk to the patient. Clinical results with the application of microwave energy have been less than satisfactory, with no demonstrated electrical isolation of the pulmonary veins. Moreover, long-term relief from atrial fibrillation has not been achieved.

Intraoperative Angiography During Minimally Invasive Direct Coronary Artery Bypass Operations

BACKGROUND The technical demands of beating heart operations raise concerns about anastomotic patency. This feasibility study tested the usefulness of intraoperative angiography during minimally invasive direct coronary artery bypass grafting (MIDCABG). METHODS Ten patients underwent intraoperative angiography of the internal thoracic artery (ITA) after MIDCABG. Minimally invasive direct coronary artery bypass grafting was performed on a beating heart through the fourth or fifth intercostal space. Angiography was performed through the right or left femoral artery with a 7F introducer system placed before the operation. Views were obtained in the right and left anterior oblique and straight anterior projections. RESULTS There were no deaths or intraoperative morbidities related to MIDCABG or angiography. Seven patients demonstrated widely patent MIDCABG anastomoses with obliteration of all intercostals, widely patent ITA pedicles, good distal runoff, and placement of the ITA into the proper native coronary artery. Two patients had revisions of their ITA pedicles, which on repeated angiography showed correction. One patients procedure was converted to a sternotomy because of poor distal runoff and haziness at the level of the MIDCABG anastomosis. CONCLUSIONS This feasibility study demonstrates the utility of intraoperative ITA angiography in identifying problems after MIDCABG. Intraoperative angiography may facilitate MIDCABG by documenting proper placement of conduits, obliteration of intercostal vessels, and patency of the MIDCABG anastomosis and ITA pedicle.

Extracorporeal Membrane Oxygenation for Adult Post Cardiotomy Cardiogenic Shock Using a Heparin Bonded System

Extracorporeal membrane oxygenation (ECMO) for adult post cardiotomy cardiogenic shock has had limited success. The efficacy of a heparin bonded ECMO system was tested in 11 patients (eight men, three women; mean age: 63 +/- 8 years), all of whom were in post cardiotomy shock refractory to inotropes and intra-aortic balloon pumping (IABP). The system consisted of a right atrial-to-aortic loop using a hollow fiber oxygenator driven by a vortex pump. All blood contact surfaces were heparin bonded. Mean duration of support was 47.9 hr (range: 22-92.5 hr). Mean prothrombin time, activated partial thromboplastin time, and activated clotting time during full support were 17 +/- 8, 57.5 +/- 38, and 152 +/- 59 sec, respectively. Mean transfusion requirements for packed red blood cells, fresh frozen plasma, and platelets were 24 +/- 9, 19 +/- 9, and 38 +/- 15 units, respectively. Complications included acute renal failure (1 patient), sepsis (3 patients), elevation of hepatic enzymes (7 patients), and myocardial infarction (11 patients). Oxygenator failure occurred in 4 patients, and 10 patients had plasma hemoglobin levels exceeding 30 mg/L. No patient experienced focal neurologic deficit. Eight (73%) patients were weaned from ECMO. Five (45.4%) of these are alive and have been discharged home with a mean follow-up of 317 +/- 76 days (range: 179-416 days). This heparin-free ECMO system allows rapid and simple deployment and provides effective short-term cardiopulmonary support.

Autogenous cardiac assist with chronic descending thoracic aortomyoplasty

Alternative surgical treatments to orthotopic cardiac transplantation are needed for patients with heart failure. We hypothesized that descending thoracic aortomyoplasty with conditioned (fatigue-resistant) latissimus dorsi muscle could provide diastolic augmentation that would improve left ventricular function. Six mongrel dogs were studied. The left latissimus dorsi muscle was wrapped clockwise around the descending thoracic aorta. Left ventricular volume was measured with a conductance catheter. Aortic and left ventricular pressures were measured with a micromanometer. The following were measured after descending thoracic aortomyoplasty at baseline and with the descending thoracic aortomyoplasty stimulated 1:1 with the heart rate: stroke work, stroke volume, left ventricular peak pressure, maximum rate of increase of left ventricular pressure, diastolic relaxation time constant, peak rate of pressure decay, left ventricular end-diastolic pressure, endocardial viability ratio, mean diastolic aortic pressure, peak diastolic aortic pressure, and time-averaged aortic diastolic velocity. Before data collection, the latissimus dorsi was stimulated (5 pulses delivered at 33 Hz at a rate of 28 per minute for 4 weeks) with burst stimulation to induce fatigue resistance. Results (expressed as the mean +/- the standard error of the mean) showed significant improvement in the indices of ventricular contractility (maximum rate of increase of left ventricular pressure, 1,217 +/- 83 to 1,414 +/- 91 mm Hg/s) and diastolic relaxation mechanics (peak rate of pressure decay, 1,152 +/- 92 to 1,282 +/- 79 mm Hg/s; diastolic relaxation time constant, 43 +/- 2 to 38 +/- 2 ms). Significant differences were noted with stimulation at 1:1 in the endocardial viability ratio (0.90 +/- 0.05 to 1.14 +/- 0.04), an index of myocardial oxygen supply. Systemic diastolic pressures (peak diastolic aortic pressure, 95 +/- 6 to 107 +/- 5 mm Hg; mean diastolic aortic pressure, 92 +/- 6 to 102 +/- 6 mm Hg) and the time-averaged aortic diastolic velocity (1.5 +/- 0.6 to 3.3 +/- 1.0 m/s) increased significantly. We conclude that descending thoracic aortomyoplasty stimulation with conditioned latissimus dorsi muscle can improve indices of ventricular contractility, diastolic relaxation mechanics, diastolic pressures, and diastolic aortic velocity in the nonfailed canine heart. Further studies with the chronic failed heart model are required.

Right Parasternal Incision: A Uniform Minimally Invasive Approach for Valve Operations☆

The right parasternal incision can be used for replacing or repairing cardiac valves. A specialized retractor system produces excellent exposure and helps avoid groin cannulation. The approach reduces surgical dissection and trauma, does not require sacrifice of mammary arteries, prevents rib spreading, avoids sternotomy, reduces the risk of cardiac injury at subsequent redo operations, and does not require specialized video or thoracoscopic equipment.

Right latissimus dorsi cardiomyoplasty augments left ventricular systolic performance

We hypothesized that the right latissimus dorsi cardiomyoplasty augments left ventricular performance. Five dogs underwent staged right latissimus dorsi cardiomyoplasty. Ventricular function was studied 1 to 3 weeks later. Left ventricular pressure was measured with a micromanometer and left ventricular dimensions with piezoelectric crystals. Inferior vena caval occlusion was used to vary preload. Pressure-volume data were collected with the muscle unstimulated and stimulated at 1:2 and 1:1 muscle/heart ratios. The end-systolic pressure-volume relation (mm Hg/mL), stroke work, preload recruitable stroke work, left ventricular end-diastolic volume, and the diastolic relaxation constant were calculated and expressed as mean +/- standard deviation. Stimulated beats at a 1:2 ratio showed an increase in stroke work of 42.1% (978 +/- 381 to 1,390 +/- 449 g.cm; p < 0.01) and preload recruitable stroke work of 28.8% (59.4 +/- 20.7 to 76.6 +/- 11.0 g.cm/cm3; p = 0.05) compared with the unstimulated beats. With the stimulator on at 1:1, smaller changes occurred: stroke work increased 9% (1,167 +/- 390 to 1,273 +/- 363 g.cm; not significant) and preload recruitable stroke work increased 27% (63.9 +/- 22.7 to 80.9 +/- 23.1 g.cm/cm3; p = 0.05). There were no significant changes in the end-systolic pressure-volume relation. The diastolic relaxation constant did not change at 1:1 (36 +/- 9.7 to 37 +/- 6.4 ms; not significant) or 1:2 (36 +/- 9.3 to 39 +/- 8.2 ms; not significant). Left ventricular end-diastolic volume was unchanged at 1:1 (34 +/- 10.7 to 32 +/- 10.3 mL) and at 1:2 (31 +/- 9.0 to 32 +/- 8.7 mL).(ABSTRACT TRUNCATED AT 250 WORDS)

Minimally invasive direct coronary bypass versus cardiopulmonary technique: angiographic comparison.

BACKGROUND Studies comparing minimally invasive direct coronary artery bypass grafting (MIDCABG) with techniques using cardiopulmonary bypass (CPB) are needed. METHODS Sixteen patients underwent single-vessel left internal thoracic artery-left anterior descending (LITA-LAD) MIDCABG through a left anterior thoracotomy, and 10 underwent multivessel bypass grafting that included a LITA-LAD, using CPB. Intraoperative completion angiography was performed on all LITA-LAD bypasses, and graded. One point each was given for: anastomotic patency, pedicle patency, intercostal obliteration, proper placement into the correct native coronary artery, and Thrombosis In Myocardial Ischemia grade III flow. RESULTS There were no intraoperative deaths or morbidities. LITA takedown averaged 49 +/- 18.6 minutes for MIDCABG and 16 +/- 2.0 minutes for CPB CABG (p < 0.05). LITA length did not differ between groups (15.3 +/- 1.2 cm for MIDCABG, 14.3 +/- 1.08 cm for CPB CABG). Ischemic arrest time was significantly less for the CPB group (13.3 +/- 8.3 minutes versus 24.5 +/- 9.6 minutes; p < 0.05). Average grade for MIDCABG LITA-LAD was 4.06 +/- 0.98 points versus 4.77 +/- 0.98 points for CPB LITA-LAD bypass (p = not significant). CONCLUSIONS Intraoperative completion angiography is feasible and, when combined with a grading system, may facilitate the comparison of MIDCABG with standard techniques.

Repair of Congenital Pulmonary Incompetence by Bicuspidization of the Pulmonary Valve

We report the successful repair of pulmonary incompetence in an adult due to the congenital absence of the posterior leaflet of the pulmonary valve. The repair consisted of bicuspidization of the pulmonary valve, which achieved competence and eliminated the symptoms and echocardiographic manifestations of right ventricular overload while preserving the native valve.