The role of coronary artery collaterals in the preservation of left ventricular function: a study to address a long-standing controversy.

INTRODUCTION: The functional significance of coronary artery collateral (CAC) vasculature in humans has been debated for decades and this has been compounded by the lack of a standard, systematic, objective method of grading and documenting CAC flow in man. CACs serve as alternative conduits for blood in obstructive coronary artery disease. This study aimed to evaluate the impact of CACs on left ventricular function in the presence of total coronary arterial occlusion. METHODS: The study group included the coronary angiographic records of 97 patients (mean age: 59 ± 8 years). CACs were graded from 0-3 based on the collateral connection between the donor and recipient arteries. Left ventricular function was computed from the ventriculogram and expressed as ejection fraction (EF). RESULTS: The mean EF of the patients with grades 0, 1, 2 and 3 CACs were calculated as 50.4, 47, 60.5 and 70%, respectively. A significant difference was recorded in the mean EF calculated for the different CAC grades (p = 0.001). There was a significant positive correlation (p < 0.001; r = 0.478) between the mean EF and the CAC grades. CONCLUSION: The patients with better coronary collateral grades had a higher mean EF. Therefore, as the grade of CACs increased, there was an improvement in their ability to preserve left ventricular function.

Coronary artery dominance dependent collateral development in the human heart.

BACKGROUND: In obstructive coronary artery disease, coronary collateral arteries serve as alternative conduits for blood flow to the myocardial tissue supplied by the obstructed vessel(s). Therefore, they are a "natural coronary arterial bypass" to the region supplied by the obstructed vessels. This study aims to determine the influence of demographic and morphologic coronary arterial factors on coronary collateral development in coronary arterial obstruction. MATERIALS AND METHODS: The study group was selected from the coronary angiographic records of 2029 consecutive patients (mean age: 59 ± 12 years). Coronary collaterals were graded from 0 to 3 based on the collateral connection between the donor and recipient arteries. The angiograms of the patients (n = 286) with total obstruction of the coronary arteries were selected for analysis. RESULTS: There were no significant association between patients' age and sex and the formation of excellent collaterals. However, the location of atherosclerotic lesion affected collateral development in the right coronary artery. In addition, the right coronary arterial dominant pattern significantly influenced the formation of excellent coronary collaterals. CONCLUSIONS: Coronary collateral arteries are better developed in right dominant pattern. It may be concluded that coronary arterial morphological pattern influences coronary collateral artery development.

Absent left main coronary artery with variation in the origin of its branches in a South African population.

Coronary artery anomalies are traditionally classified into anomalies of origin, course and termination. One of the anomalies of origin is absence of the left main coronary artery (LMCA), where the left anterior descending (LAD), the circumflex (Cx) and the ramus medianus (RM) (when present) arteries originate directly from the left aortic sinus. The study aimed to document the prevalence of absent LMCA, discuss its possible embryogenesis and clinical relevance. A review of 407 coronary angiograms performed by cardiologists of three private hospitals in the eThekwini Municipality area of KwaZulu-Natal, South Africa, was performed. The LMCA was absent in 9.6% (39/407) of the coronary angiograms. The LAD and Cx arteries originated directly from the left aortic sinus with a single ostium in 8.6% (35/407) and separate ostia in 1% (4/407) of the angiograms. In four of the angiograms with absent LMCA, a RM artery was recorded originating directly from the left aortic sinus in addition to the LAD and the Cx arteries. Angiographic detection of the anomalies of the coronary arteries is essential in the determination of the significance of such findings and their management.

The intramyocardial left anterior descending artery: prevalence and surgical considerations in coronary artery bypass grafting.

BACKGROUND: Major coronary arteries usually have a subepicardial course and only dip into the myocardium near or at their termination. However, occasionally a segment of the epicardial artery may have an intramural course, and it is often referred to as a myocardial bridge. The left anterior descending (LAD) artery is the most commonly bridged vessel. Its prevalence has been evaluated at both autopsy and angiography. However, in the literature reviewed it is apparent that there are no reports of the prevalence of the intramyocardial LAD (IMLAD) artery in coronary artery bypass graft (CABG) series. OBJECTIVES: To document the prevalence of the IMLAD artery in a series of CABGs and to describe the surgical techniques used in these cases. METHODS: A retrospective analysis of 1349 surgical reports of consecutive CABGs performed over a period of 23 years was conducted. RESULTS: An IMLAD artery was present in 293 patients (21.7%). The prevalence was 20.2% (51/253) in females and 22.1% (242/1096) in males. The IMLAD arteries extended into the interventricular septum in 3.8% (11/293) of the patients. CONCLUSION: An intramyocardial course of the LAD artery is relatively common in patients undergoing CABG and poses a challenge in bypass grafting. Techniques are described to address this anatomical variation when it is encountered at surgery.

Anatomic parameters of the left coronary artery: an angiographic study in a south african population / Parámetros anatómicos de la arteria coronaria izquierda: estudio angiográfico en una población sudafricana

An understanding of the left coronary artery (LCA) anatomy is important for accurate diagnosis and therapeutic intervention in the management of coronary arterial diseases. This angiographic study aims to document the parameters of the LCA that may be of importance in the diagnosis and treatment of coronary artery diseases. An analysis of 151 coronary angiograms obtained from the cardiac catheterization laboratory in the eThekwini Municipality area of KwaZulu-Natal, South Africa was performed. The mean length and diameter of the LCA were 10.4+/-4.1 mm (range 2.8-23.9 mm) and 3.8+/-0.8 mm (range 2.1-6.5 mm), respectively. The mean angle of division between the two main branches was 86.2°+/-26.1° (range 27°-68.5°). There was a positive correlation between the length and the angle of division of the LCA, with the longest LCAs having the largest angle of division. The branching patterns of the LCA were 80.8 percent, 18.5 percent and 0.7 percent for bifurcation, trifurcation and quadrifurcation, respectively. Coronary arterial dominance was 81.5 percent, 15.2 percent, and 3.3 percent for right, left, and co-dominance, respectively. This study corroborated earlier findings that the longer the length, the wider the angle of LCA division. A wide angle of LCA division, the shape and disposition of the proximal tract of LCA branches may affect flow, interfere with proper deployment of stents or may predispose to earlier atherosclerotic lesions.

La comprensión anatómica de la arteria coronaria izquierda (ACI) es importante para el diagnóstico e intervención terapéutica en el tratamiento de enfermedades arteriales coronarias. Este estudio angiográfico tuvo como objetivo documentar los parámetros de la ACI que pueden ser de importancia en el diagnóstico y tratamiento de enfermedades de las arterias coronarias. Se realizó el análisis de 151 angiografías coronarias obtenidas del laboratorio de cateterización cardíaca en el área del Municipio eThekwini de KwaZulu-Natal, Sudáfrica. La longitud y diámetro promedio de la ACI fueron 10,4+/-4,1 mm (rango 2,8 a 23,9 mm) y 3,8+/-0,8 mm (rango de 2,1 hasta 6,5 mm), respectivamente. El ángulo medio de la división entre las dos ramas principales fue 86,2°+/-26,1° (rango 27°­168,5°). Hubo una correlación positiva entre la longitud y el ángulo de división de la ACI, donde las ACI más largas tuvieron un ángulo de división más grande. Los patrones de ramificación de la ACI fueron porcentualmente 80,8 por ciento, 18,5 por ciento y 0,7 por ciento para bifurcación, trifurcación y quadrifurcación, respectivamente. La dominancia arterial coronaria fue del 81,5 por ciento, 15,2 por ciento y 3,3 por ciento para la derecha, izquierda y en co-dominio, respectivamente. Este estudio corrobora hallazgos anteriores en que cuanto mayor sea la longitud, mayor será el ángulo de la división de ACI. Un amplio ángulo de la división de la ACI, la forma y la disposición del tracto proximal de las ramas de la ACI pueden afectar el flujo, interferir con el despliegue apropiado de los stents o predisponer a las lesiones ateroscleróticas tempranas.

The impact of left main coronary artery morphology on the distribution of atherosclerotic lesions in its branches.

BACKGROUND: Atherosclerotic occlusion of a coronary vessel is the commonest cause of ischaemic heart disease. The distribution of atherosclerotic lesions is not random,with stenoses preferentially situated at branch ostia, bifurcation points, and the proximal segments of daughter vessels. The aim of this study was to determine the effect of the intrinsic anatomical properties of the left main coronary artery(LMCA) on the distribution of atherosclerotic lesions in its branches. MATERIALS AND METHODS: A retrospective review of 170 consecutive coronary angiograms obtained from the cardiac catheterisation laboratories of private hospitals in the eThekwini Municipality area of KwaZulu-Natal, South Africa was performed. The LMCA was absent in 19/170 (11.2%). The remaining angiograms(n = 151) were divided into two groups: normal 63/151 (41.7%) and those with coronary artery disease (CAD) 88/151 (58.3%). The CAD group was sub-divided into proximal 42/88 (47.7%), mixed (proximal and distal) 26/88 (29.6%) and distal20/88 (22.7%) sub-groups based on the location of atherosclerotic lesions in the branches of the LMCA. RESULTS AND CONCLUSIONS: The mean length, diameter and angle of division of the LMCA were as follows: Total angiograms: 10.4 mm, 3.8 mm and 86.2o; normal group:10.5 mm, 3.9 mm and 85.7o, CAD group: 10.2 mm, 3.7 mm and 86.3o; proximal sub-group: 10.9 mm, 3.7 mm and 91.6o, mixed sub-group - 9.8 mm, 3.7 mm and 85o and distal sub-group - 9.1 mm, 3.8 mm and 79.4o, respectively. The vessels with proximally located lesions were recorded to have longer lengths and wider angles of division than vessels with distal lesions. Coronary angiographic delineation of the LMCA anatomy may be predictive of a coronary arterial arrangement that may favour the progression of proximally located lesions.

The prevalence and clinical importance of an "additional" terminal branch of the left coronary artery.

The left coronary artery (LCA) usually divides into two (anterior interventricular artery [AIA] and left circumflex [LCx] artery) or less frequently into the AIA, LCx,and one or more "additional" terminal branch/es (ATBs). These ATBs of the LCA have no unanimity regarding their anatomical nomenclature. There is a lack of common consensus on the criteria used for their definition, and they are also absent from the current Terminologia Anatomica (1998). This study, therefore,aimed to document the prevalence of the ATBs of the LCA, discuss their clinical importance, and propose an anatomical nomenclature. This study was conducted by reviewing 367 coronary angiograms. The termination patterns of the LCA were classified into 3 categories based on the number of their branches, viz. (a) bifurcation78.2%, (b) trifurcation 20.4%, and (c) quadrifurcation 1.4%, respectively. The presence of an ATB was recorded in 21.8% of the angiograms. The identification of this vessel may be of clinical importance because the extent of its supply may decrease the effect of occlusion of the LCx artery and AIA on the myocardium.The term "left ramus medianus artery" is proposed as the nomenclature for the ATB of the LCA.

Pericardiectomy: a functional anatomical perspective for the choice of left anterolateral thoracotomy.

Although pericardiectomy remains an established method for pericardial resection, the choice of surgical approach is not definitive. Within South Africa, surgical referral for tuberculosis-induced chronic constrictive pericarditis has not declined. Anecdotal reports have indicated good operative results that appear to show an association with choice of surgical technique used. This study aimed to provide a functional anatomical perspective for performance and recovery of the heart during pericardiectomy based on anatomical dissection and surgical notes. En bloc specimens were harvested from 16 fresh cadavers and pericardial segments were measured in terms of percentage cover over surface area of the myocardium. Retrospective analysis of 116 surgical reports of pericardiectomy performed over a period of 20 years was conducted. Surgical notes were compared for median sternotomy and anterolateral left thoracotomy. Results from anatomical study indicated that although the anterior pericardium between the phrenic nerves constitutes about 58% of total selected pericardial area, total pericardium accessible over left ventricle from that approach was only 26%. When orientated in left anterolateral position, total accessible area of left ventricular pericardium was 37%. Standard deviations were found to be comparable. Means were significantly different, indicating that the left anterolateral approach allows wider access to the left ventricle. This paper provides a functional anatomical perspective for the choice of left anterolateral thoracotomy as a surgical approach for pericardiectomy.

Clinical significance of internal thoracic artery morphometry and inter-ethnic differences.

The internal thoracic artery (ITA) is used extensively for coronary revascularisation. Clinical observations suggest an inter-ethnic difference in ITA morphometry between Indians and whites presenting for coronary artery bypass surgery. However, accurate morphometric data comparing these ethnic groups were not available. This study analyses the morphometry of the left and right ITAs in 60 cadavers (43 blacks, 9 whites, 8 Indians). The lengths of the arteries were measured and the external diameters were recorded at the origin of the 1st, 4th and 6th costal cartilages. Significant differences in length and diameter on the right and left sides between ethnic groups were demonstrated. In particular, these differences were marked between the white and Indian groups. Clinically, these differences can be so marked that in some instances the left ITA in Indian patients is so small at the distal point of take-down as to be unsuitable for use as an arterial conduit. This is one of the reasons that has prompted the use of the ITA as a composite graft. Our study appears to be the first to highlight this inter-ethnic difference and to support the clinical impression.

Internal mammary artery haematoma.

Traumatic disruption of the internal mammary artery, which produces a well-circumscribed haematoma in the extrapleural plane and not a haemothorax, has not been described previously in English-language reports. Both blunt and penetrating trauma may be the cause. Ten such cases have been identified and verified by angiography.

Colon bypass from the oral cavity.

A young man had had caustic burns of the pharynx, larynx, esophagus, and stomach 4 years previously. Total gastrectomy had been performed, and nutrition was maintained through a jejunostomy feeding tube. Alimentary continuity was restored with an isolated colon segment, brought substernally to the oral cavity, with excellent results.

A surgical approach to aortic arch aneurysms presenting through the sternum.

A surgical approach to the repair of aortic arch aneurysm presenting through the sternum is described. A limited right anterior thoracotomy is made to gain access to the right and left atria. A vertical sternotomy is made only after profound core hypothermia has been achieved and the fibrillating left ventricle decompressed. The circulation is arrested and the patient exsanguinated during sternotomy, providing controlled conditions should the aneurysm be entered.