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Notes: The metric-affine gauge theory of gravity encompasses a space-time with the following geometrical fields: coframe cursive-thetaα, metric g, and an independent linear connection Γαβ. Within this geometrical framework, all four-forms B=dC are constructed which qualify as boundary terms for a gauge Lagrangian, that is, they are GL(4,R)-scalars as well as exact forms derived from Chern–Simons type three-forms C. The result of our search is summarized in Eq. (4.20). The translational piece dCTT is new. The boundary terms effectively serve as Lagrangians for the Bianchi identities of nonmetricity, torsion, and curvature. In the canonical formalism, the normal parts of the Chern–Simons three-forms represent generating functions that are capable of generating new Ashtekar type variables. Eventually, the Bach–Lanczos identity is generalized to the metric-affine space-time.

Notes: We have developed a complete excimer laser and fiber-optic angioplasty system and successfully opened completely occluded blood vessels in humans. We use the 308 nm XeCL excimer laser and fiber-optic delivery system that can be passed through a catheter or over a guidewire. In this article, we describe the knowledge essential for the interventionalist using the device: the method for generating 308 nm laser light, laser-tissue interaction, healing after laser injury, and how the rate of laser ablation is controlled. Our initial experience using the excimer laser in the superficial femoral artery has been excellent. (J of Interv Cardiology; 1988;1:1)

Notes: Background and aim of the study: Early graft failure is often associated with technical failures and is therefore potentially avoidable. We used thermal coronary angiography (TCA) for intraoperative graft patency control in 370 patients undergoing routine coronary artery bypass graft surgery to determine whether consequent intraoperative bypass graft control may result in improved patency rates. Methods: The temperature differences generated in between the myocardium and the grafts by injecting cold cardioplegic solution into the proximal end of a vein graft or by warmer blood running through an internal thoracic artery (ITA) graft were detected using three different infrared camera systems. The resulting “heat pictures” were evaluated for anastomotic patency and to outline graft anatomy. Results: A total of 693 vein grafts were visualized. In 9.4% TCA failed to produce usable images. In the remaining 628 grafts, TCA revealed intraoperative patency in 98.8%. Out of 370 ITA grafts, only 14 could not be sufficiently visualized by TCA. Nineteen ITA occlusions (5.3%) were found: 5 intimal flaps; 11 suture imposed strictures; and 3 proximal ITA occlusions. All occluded grafts were subsequently revised or replaced. All sequential ITA as well as 15 right ITA grafts proved to have patent anastomoses. Conclusion: Using TCA an early graft dysfunction rate of 1% for vein grafts and 5.3% for ITA grafts could be demonstrated. Most occlusions were due to technical mistakes at the distal anastomosis. TCA outlines grafts and the attached coronaries by temperature differences without the need for a contrast agent. There is no interference with the surgical procedure. It is an ideal, noninvasive method to immediately document the success or failure of myocardial revascularization.

Notes: Background: The indications for operative intervention for symptomatic hypertrophic obstructive cardiomyopathy (HOCM) in infancy and childhood are not well defined because of the rarity of the lesion. The traditional surgical procedure consists of septal myectomy. In an attempt to further improve the outcome of HOCM associated with concentric left ventricular hypertrophy and aortic valve disease in infancy, we have combined resection of the left ventricular septum and free wall with a Ross-Konno procedure. Methods: Three infants (aged 3, 4, and 10 months) with HOCM (left ventricular aortic gradients of 75, 95, and 110 mmHg), associated concentric left ventricular hypertrophy, and valvar aortic stenosis (n = 1) or combined valvar aortic stenosis and regurgitation (n = 2) underwent extensive resection of fibroelastosis and subendocardial myocardium of the left ventricular septum and free wall in combination with a Ross-Konno operation. All three patients had marked systolic anterior motion of the mitral valve. The length of the incision into the ventricular septum was 1.8, 2.0, and 2.3 cm. Results: In all three patients this procedure resulted in a marked reduction of width of the left ventricular septum (median 9 mm vs 14 mm preoperatively) and the left ventricular posterior free wall (median 8 mm vs 12 mm preoperatively) and an almost twofold increase of the left ventricular end-diastolic volume (median 13.5 cm3 vs 7.0 cm3 preoperatively). The neo-aortic valve functioned normally. Systolic anterior motion of the anterior leaflet of the mitral valve had completely resolved in two patients and had markedly regressed in the remaining patient. At follow-up of 15, 17, and 26 months, two patients had absence of a left ventricular outflow tract gradient and the third patient had a residual sub-valvar gradient of 15 mmHg. Conclusions: The reported procedure may be a valuable technique in severe forms of hypertrophic cardiomyopathy associated with aortic valve disease. The operation results in enlargement of the left ventricular stroke volume and improvement of the left ventricular diastolic function, restores aortic valve anatomy and function, and abolishes or decreases systolic anterior motion of the mitral valve.

Notes: Abstract In repair of coarctation in neonates or young infants, inadequate removal of ductal tissue, failure to address hypoplasia of the aortic arch, and suture line tension have been reported to be important factors of residual or early recurrent stenosis at the coarctation repair site. In a consecutive series of neonates and young infants with coarctation, who were all operated without delay with extended resection, the clinical outcome regarding the development of restenosis and hypertension was studied. In addition, the resected specimens were investigated regarding the completeness of resection of ductal tissue. Twenty-five consecutive neonates and young infants (median age 22 days, range 5 to 39 days) who underwent surgical correction of coarctation were reviewed; the resected specimens were examined histologically to document the extent of ductal tissue in the aortic wall. Fifteen patients had a preductal coarctation with associated cardiovascular anomalies including a hypoplastic aortic arch (n = 11). The remaining 10 patients had a paraductal coarctation without associated intracardiac anomalies. In all patients, the isthmus was bypassed and an end-to-side anastomosis was constructed between the descending aorta and the undersurface of the proximal aortic arch (n = 13) or the distal ascending aorta (n = 12). In 13 patients without marked hypoplasia of tbe aortic arch, the coarctation repair was performed through a left thoracotomy. In the remaining 12 patients, the coarctation was repaired through a median sternotomy with CPB and hypothermic circulatory arrest, on the basis of an associated hypoplastic aortic arch (n = 4), hypoplastic aortic arch with intracardiac anomalies (n = 7), or a “bovine” innominate artery (n = 1). There was no perioperative or late mortality. At a median follow-up of 15 months, 1 patient (4%) developed a recurrent stenosis at the coarctation repair site; in the remaining 24 patients, echocardiograpby showed a widely patent anastomosis with no evidence of a hemodynamically significant gradient. None of the patients had hypertension. Histologic examination of the resected specimens demonstrated the presence of ductal tissue in the descending aorta with maximal extension into its lateral wall (mean 5.2 mm). In all specimens of the paraductal subtype, there was also extension of ductal tissue into the lateral wall of tbe isthmus (mean 3.9 mm). We conclude that: (1) in the absence of marked hypoplasia of the proximal aortic arch, coarctation can be repaired with low mortality and morbidity via a left thoracotomy; (2) in the presence of marked hypoplasia of the proximal aortic arch and/or if associated intracardiac defects also need to be repaired, we advocate repair of the coarctation and associated defects through a median sternotomy with circulatory arrest; (3) in view of the absence of postoperative hypertension in this series, early repair of aortic coarctation is recommended; and (4) because ductal tissue may extend not only into the descending aorta but also into the isthmus, complete excision of the coarctation and bypass of the isthmus are valuable techniques to avoid secondary constriction of the aorta by ductal tissue.