Left ventricular apex to descending aorta valved conduit: description of transthoracic and transesophageal echocardiographic findings in four cases.

Patients with critical aortic stenosis and a "porcelain" aorta are at an increased risk for complications with aortic cross-clamping during valve replacement. To our knowledge, this is the first report of both transthoracic and transesophageal echocardiographic findings of the left ventricle to the descending aorta (LVDA) valved conduit. We present results of four patients in whom this procedure was performed for critical aortic stenosis, who also had a porcelain aorta. "Normal" echo and Doppler findings, along with those of development of a regurgitant valve within the conduit, are presented.

Vein graft failure.

Saphenous vein graft failure is one of the primary reasons for coronary artery bypass reoperation. The economic impact alone in this country is staggering in an era of intensive cost cutting. The fact that some vein grafts remain free of disease for years while the sibling vein develops extensive atherosclerosis remains an enigma. Saphenous vein valves have recently attracted interest. Repeated angiograms show that vein graft disease invariably is accentuated around valves. Studies show that the segment of saphenous vein distal to the valves have more accelerated and intense atherosclerosis. Early results of saphenous vein bypass grafting may be predicted with some degree of certainty by saphenous vein graft biopsy. Attention is now being turned to the hypercoagulable state as a cause of graft failure, as this has not been previously addressed. Research into pharmacologic agents for maintaining open grafts has had disappointing results and aspirin alone is still the single drug of choice to promote patency. Preparation of the graft continues to be important because there is direct evidence that surgical injury during preparation leads to neointimal thickening and vascular smooth muscle proliferation. Although there are some exciting new modalities for preventing graft disease, the difficulty in transposing animal data to humans and the uncertainty of the biologic similarities of in vitro and in vivo endothelial cell biochemistry makes any immediate solution unlikely. Therefore an even greater increase in the use of arterial grafts in the near future seems likely, even with their associated problems.

Right gastroepiploic artery used for coronary artery bypass grafting. Evaluation of flow characteristics and size.

Questions remain concerning the physiologic capabilities of the right gastroepiploic artery as a bypass graft in the clinical setting. Our last 90 consecutive pedicle right gastroepiploic artery grafts were prepared with intraluminal papaverine and verapamil. Our series comprised 81 male and 9 female patients with average body surface areas of 1.92 m2. Ages ranged from 11 to 79 years (mean 57.2 years). A second to fourth revascularization was undertaken in 32 patients (35.5%). The following arteries were bypassed: posterior descending artery, 63; right coronary artery, 23; distal right, 4; circumflex, 2; left anterior descending, 1; and diagonal, 1. Free flow rates ranged from 42 to 660 ml/min (mean 179.96 ml/min). Internal diameters measured 1.5 to 4.0 mm (mean 2.20 mm) at the anastomotic sites. Pedicle lengths ranged from 16 to 26 cm (mean 19.2 cm). Inotropic support was required in 11 patients (12%) and had no adverse effects on right gastroepiploic artery grafts. There were 2 hospital deaths (2.2%). Angina has recurred in 6 patients. One patient with cardiomyopathy required transplantation 2 years after coronary bypass grafting. Repeat angiography showed widely patent grafts in 18 patients and generalized narrowing in 4 grafts. In only 2 patients of our total experience has right gastroepiploic artery grafting been aborted because of inadequate conduit size. One right gastroepiploic artery had visible atherosclerosis. This study shows that distal right gastroepiploic artery sizes are comparable with sizes of target coronary arteries. However, neither flow nor size is as consistent when compared with internal thoracic artery grafts. Higher flow rates are related to graft anatomic characteristics and larger body surface areas. Spasm, secondary to harvest in these vasoreactive grafts, can be managed appropriately by intraluminal vasodilating drugs. However, use of the right gastroepiploic artery should be avoided in a setting with possible competition of flow.

Technical advances in the treatment of left ventricular aneurysm.

The resulting abnormal geometry after surgical treatment of left ventricular aneurysm has concerned a number of surgeons since the first successful repair in 1958, but little attention was placed on the altered geometry until attempts were made to effect a more physiologic aneurysmorrhaphy in 1973. Substantial attention was focused on a concept of geometric reconstruction from within the left ventricle in 1985. A prosthetic patch was employed with the concept to redirect normal muscle bundles to their original orientation and position. Further refinements include use of improved materials for the repair, preservation and bypass of the left anterior descending coronary artery, ablation of ventricular arrhythmias when indicated, and the absence of prosthetic material used in contact with the pericardial surface. Our experience with repair of 61 left ventricular aneurysms at West Jefferson Medical Center over a 4 1/2-year period with a 3.3% mortality rate has prompted a change from the standard linear repair to routine use of a modified endoventricular repair. Currently, the low surgical risk due to advances in left ventricular aneurysmorrhaphy combined with the knowledge that contractile areas will progressively deteriorate in ventricles stressed by poor hemodynamics and with data showing improved left ventricular function postoperatively have led to more liberal recommendations for early left ventricular aneurysm repair.

The subscapular artery: an alternative conduit for coronary bypass.

The search for an alternative conduit for coronary bypass has prompted our use of the subscapular artery for coronary bypass via a left thoracotomy in three patients. Historically, this artery in conjunction with muscle flaps has been used successfully as a free graft. Its size and length have proved feasible for coronary bypass to the circumflex coronary artery system. All three patients have had excellent clinical results lasting from 6 to 21 months.

Free arterial grafts.

The use of free arterial grafts has increased since the late patency of free internal mammary artery grafts was found to approach that of pedicle internal mammary artery grafts. An intensified search for other suitable arterial grafts has resulted in reports on the use of free gastroepiploic artery grafts and free inferior epigastric artery grafts. Free arterial heterografts and free homograft saphenous veins have had very disappointing results in general. The lateral costal artery, when available, offers another possible arterial conduit in approximately 10% of patients. To effect a wider use of arterial conduits for coronary bypass grafts, a number of techniques have been devised to use the internal mammary artery and other arterial grafts as free grafts.

Atherosclerosis of the ascending aorta and coronary artery bypass. Pathology, clinical correlates, and operative management.

Analysis of 1735 patients who underwent coronary artery bypass grafting from January 1981 through December 1988 revealed 152 (8.8%) patients with mild (4.5%), moderate (2.2%), or severe (2.0%) atherosclerosis of the ascending aorta. Three distinct pathologic patterns were found. The prevalence of stroke in patients with the severe type of aortic disease prompted development of a new operative technique that has been used in 16 patients. It involves a "no-touch" technique of the ascending aorta whereupon the proximal saphenous vein anastomoses are performed end to side to internal mammary artery grafts. Ages ranged from 49 to 80 years (mean 68.9). The 16 patients had 62 distal artery and vein anastomoses and 26 proximal saphenous vein-internal mammary end-to-side anastomoses. Internal mammary artery free flows ranged from 130 to 420 ml/min. Two hospital deaths were unrelated to the technique. There have been no strokes or recurrences of angina. An inordinately high incidence of main left coronary disease (50%), significant carotid disease (79%), and abdominal aortic occlusive or aneurysm disease (93%) was discovered. Ascending aortic atherosclerosis must be suspected in all coronary bypass patients with associated significant carotid, abdominal aortic, and main left coronary artery disease, aortic wall irregularity on ascending aortic angiography, adhesions between the ascending aorta and its adventitia, pale appearance of the ascending aorta, and minimal bleeding of an aortic cannulation stab wound. A "no-touch" technique that avoids any manipulation of the ascending aorta and that uses the internal mammary arteries as the sole source of blood supply for coronary bypass is an effective method to prevent aortic clamp injury, "trash heart," or stroke from severe ascending aortic disease. Preoperative angiographic visualization of the ascending aorta of all patients undergoing coronary artery bypass is mandatory.

Technical considerations for myocardial protection during the course of coronary artery bypass reoperation: the impact of functioning saphenous vein and internal mammary artery grafts.

New technical challenges involving the delivery of cardioplegia during the course of coronary artery bypass operation continue to be presented to the surgeon. Functioning saphenous grafts at reoperation that are at risk for distal embolization, are managed by altering the standard cardioplegia delivery techniques. Management of patent internal mammary artery (IMA) grafts depends upon the status of the native circulation and coronary collateral. The reoperation may be performed with a fibrillating heart, standard cardioplegia with a clamped mammary graft, or cardioplegia delivered during simultaneous circulatory arrest. Myocardial temperature measurements, during the course of more complex operations, are useful in choosing the appropriate technique for myocardial protection.

Technique for use of the inferior epigastric artery as a coronary bypass graft.

A search for a coronary bypass conduit with increased longevity has resulted in harvest of the inferior epigastric artery. The artery is dissected through a paramedian incision with retraction of the rectus muscle to the lateral side. As the inferior epigastric artery courses superiorly, it may lie in one of three positions in relation to the rectus muscle. Distal coronary anastomoses using this conduit are conventional, and the proximal anastomosis may be made to the aorta or end-to-side to an internal mammary artery or venous conduit. After preparation with dilute papaverine-Plasmalyte solution proximal sizes have ranged from 2.5 to 3.25 mm (internal diameter), and distal inferior epigastric artery sizes measured 1.5 to 2.5 mm (internal diameter). The lengths of the conduit ranged from 11.5 to 17.0 cm. Eighteen patients aged 41 to 74 years had inferior epigastric artery grafts to 19 coronary arteries. The indications for use were absent or poor-quality vein, young age with an attempt to limit vein graft, and avoidance of use of bilateral internal mammary artery grafts in insulin-dependent diabetic patients. There was one sterile wound hematoma and one late wound infection. There were no other infections and no deaths. Three patients studied postoperatively revealed widely patent inferior epigastric artery grafts.

Newer surgical techniques in myocardial revascularization.

Recent trends in the patient population coming for surgical treatment of coronary artery disease have prompted alterations in the type of coronary artery bypass surgery performed. Emphasis is placed on the more widespread use of arterial grafts and revascularization of vessels with extensive distal disease, utilizing endarterectomy techniques, in an attempt to provide a more complete and long-lasting revascularization.

Right gastroepiploic artery: a third arterial conduit for coronary artery bypass.

Experience with 39 patients (32 men, 7 women) undergoing coronary artery bypass grafting with the right gastroepiploic artery (RGEA) is reported. Indications initially included poor-quality or absent saphenous vein, ascending aortic atherosclerosis, and repeat coronary artery bypass grafting. The average number of grafts per patient was 4.10. Arteries bypassed were the posterior descending (22 patients), right coronary (12), diagonal (5), and marginal (4). Distal RGEA internal diameters of all grafts measured 1.5 to 3.25 mm (average diameter, 2.14 mm). Pedicled graft lengths measured 18 to 30 cm (average length, 23.7 cm), and free grafts, 8 to 24 cm (average length, 17.7 cm). In 6 patients, no vein grafts were used, and in all patients, at least one internal mammary artery graft was placed. Early postoperative cardiac catheterization (19 pedicled and ten free grafts) in 29 patients revealed all grafts to be patent without a kink or twist, but three of these free RGEA grafts had vasospasm. Advantages of RGEA grafts are as follows: (1) it is a third arterial conduit with artery-artery anastomoses of comparable sizes; (2) a shorter leg incision or no leg incision is necessary; (3) it can be harvested simultaneously with the internal mammary artery and the saphenous vein; (4) the proximal anastomosis (free grafts) is easy; (5) its use avoids bilateral internal mammary artery grafts in patients at high risk for sternal infection; and (6) atherosclerotic ascending aortas are not clamped. Subintimal hyperplasia and atherosclerosis of RGEA grafts are unlikely.(ABSTRACT TRUNCATED AT 250 WORDS)

Technical considerations for use of the gastroepiploic artery for coronary artery surgery.

Disappointing long-term results with saphenous vein graft (SVG) for coronary bypass and excellent long-term results with internal mammary artery (IMA) to coronary bypass have prompted a search and research for other alternative coronary bypass conduits. Experience with the radial artery was disappointing due to early failure of those grafts. Likewise, conduits of artificial materials and homograft veins have not produced acceptable long-term results.

Dynamic right ventricular dimension. Relation to chamber volume during the cardiac cycle.

Whereas the left ventricle has been analyzed extensively, the apparent complexity of right ventricular geometry and contraction has hindered analysis of right ventricular performance by an assessment of instantaneous ventricular dimensions and volume during the cardiac cycle. To address this issue, we examined the temporal and quantitative relation between dynamic right ventricular free wall dimension, rate of pressure development (dP/dt), and pulmonary artery flow in the open-chest dog. Right ventricular free wall chord dimension was recorded by sonomicrometry, right ventricular pressure by micromanometer-tipped catheter, and pulmonary flow by electromagnetic probe. The point of peak positive right ventricular dP/dt closely correlated with the end of isovolumic contraction and initiation of ejection, occurring within 10 +/- 25 msec of initiation of pulmonary flow. Right ventricular dimension at peak positive dP/dt differed from dimension at initiation of chord shortening by less than 3%. Peak negative dP/dt correlated with end ejection, occurring within 10 +/- 25 msec of cessation of pulmonary flow. Right ventricular dimension at peak negative dP/dt differed from minimal dimension by less than 1%. In all dogs, volume ejected from the right ventricular chamber during each cardiac cycle was directly related to the change in right ventricular dimension during the same period (mean r = 0.969). This relationship between right ventricular stroke volume and dimensional change remained linear and was not changed (p = NS) by increases in right or left ventricular afterload induced by constricting the pulmonary artery or descending aorta. Right ventricular stroke work, calculated as the integral of instantaneous right ventricular pressure and dimension, correlated well (mean r = 0.980) with directly measured global right ventricular stroke work over a wide range; it was also not changed (p = NS) by changes in afterload. Accurate assessments of beat-to-beat right ventricular chamber volume and stroke work can be obtained by analysis of dynamic right ventricular chord dimension.

Enflurane enhances postischemic functional recovery in the isolated rat heart.

Enflurane is a direct myocardial depressant and may act as a myocardial protective agent during ischemia. The authors studied the effects of enflurane on myocardial high-energy phosphates and tolerance to ischemia in the normothermic, isolated rat heart. After isolation and perfusion with Krebs-Henseleit buffer, the hearts were perfused with either buffer (control) or buffer gassed with 2% enflurane for 10 minutes. Thereafter, hearts were made globally ischemic and elapsed times to initiation of ischemic contracture (IC) were determined. ATP and creatine phosphate (CP) were measured at the conclusion of control and enflurane administration and at IC. Ten hearts per group were reperfused with buffer following IC for 20 min; peak pressure and ATP and CP were determined. Administration of 2% enflurane significantly decreased peak pressure by 20% but did not alter baseline high-energy phosphate levels nor did it prolong time to IC. However, enflurane-treated hearts exhibited significantly greater (P less than 0.01) recovery of function as defined by per cent return of peak pressure (67% +/- 3%) when compared with those hearts not treated with enflurane preischemically (44% +/- 5%). Also, enflurane-treated hearts had significantly higher (P less than 0.01) ATP levels at the conclusion of reperfusion than hearts not perfused with enflurane (12.2 +/- .8 mumol/g dry weight vs. 9.0 +/- 0.8 mumol/g dry weight). These findings suggest that enflurane administered prior to an ischemic interval enhances postischemic myocardial recovery.