Spontaneous left main coronary artery dissection

Spontaneous coronary artery dissection is a rare and generally fatal disease. A review of the literature demonstrates that the aetiopathogenesis of the disease is unknown and that the histology is rarely described. It usually occurs in young women during the post-partum period or while taking oral contraceptives. The treatment depends on the clinical presentation and the results of the angiography. We report here a case of spontaneous dissection of the left main stem coronary artery, with extension into the left coronary territory which which occurred in a 43-year-old woman.     

Myocardial protection by retrograde cardioplegic perfusion through the right atrium

Three types of cardioplegic delivery with ink into the isolated canine hearts were compared: (1) antegrade aortic root perfusion (AARP), (2) retrograde coronary sinus perfusion (RCSP) and (3) retrograde right atrium perfusion (RRAP). Ink was not distributed in the area distal to the coronary occlusion by AARP but well distribution in the same area by RCSP or RRAP. The right ventricular wall and ventricular septum were poorly perfused by RCSP but well perfused by RRAP. During cardiopulmonary bypass, RRAP created a fairly rapid cardiac arrest and satisfactory myocardial cooling. During Perfusion, the right heart was somewhat dilated but all the 10 canine hearts rebeat well. The left and right ventricular ejection fraction showed no significant change after bypass. No marked myocardial ultrastructural injury was found in left and right ventricles at the end of 90 minutes' ischemia. 4 patient, 1 of whom had 162 minutes' aortic cross-clamping received RRAP in operations on ascending aorta or coronary arteries and the myocardial protect ion was satisfactory. No complication was found pertaining to RRAP.     

Surgery for acute type A dissection using antegrade selective cerebral perfusion: experience with 122 patients

BACKGROUND: Antegrade selective cerebral perfusion (ASCP) has proved to be a reliable method of brain protection during surgery of the thoracic aorta, but its use during aortic dissection surgery still remains controversial. In this study, we present our results after the operative repair of acute type A aortic dissections using ASCP and moderate hypothermic circulatory arrest. METHODS: Between October 1995 and August 2001, 122 patients (76 men, 46 women) underwent repair of acute type A aortic dissection with the aid of ASCP and open distal anastomosis. The average age of the patients was 61 +/- 12 (mean +/- standard deviation). Preoperative complications included cardiac tamponade (n = 34; 27.0%), aortic regurgitation (n = 27; 22.1%), and new neurological deficits (n = 11; 9%). RESULTS: Stepwise logistic regression revealed preoperative cardiac tamponade (p = 0.018) and new neurological deficits (p = 0.017) to be independent determinants for hospital mortality (19.7%). Permanent neurological complications occurred in 7% of the patients. Independent risk factors for temporary neurological dysfunction (11.2%) included cardiac tamponade (p = 0.019) and preoperative neurological deficits (p = 0.000). CONCLUSIONS: In our experience, the surgical treatment of acute type A aortic dissection with the aid of ASCP was associated with acceptable hospital mortality and neurologic morbidity rates.     

Mediastinal hematoma and left main dissection following blunt chest trauma.

A 40-year-old man sustained blunt chest trauma resulting in sternal fracture, mediastinal hematoma, and dissection of the left main coronary artery. Because of associated injury, the coronary angiogram was performed 7 days after the accident and off-pump coronary bypass surgery was performed immediately. Two months later, follow-up angiogram revealed completely healed left main dissection. The patient continues to do well 4 months postoperatively.     

Myocardial protection by intermittent perfusion with cardioplegic solution versus intermittent coronary perfusion with cold blood

The myocardial protection provided by cardioplegic solution using buffered, isosmotic potassium (30 mEq. per liter) was compared with intermittent cold coronary perfusion for 2 hours of aortic cross-clamping in dogs. The cardioplegic solution (Group CS) or cold blood (Group CB) was infused every 15 minutes through a cooling coil to reduce the perfusate temperature to 5 degrees C. Myocardial function after 30 minutes of reperfusion and rewarming was reduced in Group CB with a significant reduction in peak systolic pressure at a left ventricular (LV) balloon volume of 20 ml. and a significant reduction of dp/dt. In contrast, in Group CS, LV function was unchanged from the base-line period. LV compliance also was significantly reduced in Group CB while being unchanged in Group CS. Myocardial extravascular water content, obtained by dessication, was significantly higher in Group CB than in Group CS, which may explain the reduction in compliance. Electron microscopy showed normal ultrastructure in Group CS but extracellular edema in Group CB. Total coronary blood flow showed a sustained increase during reperfusion in both groups. Oxygen consumption rose with rewarming to base-line levels in both groups, whereas lactate and pyruvate consumption was reduced in both groups, particularly Group CB. Cardioplegic solution thus appears to be superior to the intermittent perfusion of cold blood for myocardial protection. The addition of potassium arrest, by markedly reducing myocardial metabolism, improves the protection afforded by cold blood perfusion alone.     

The distal perfusion first technique for complicated stanford type B aortic dissection.

We present a new technique, which is the distal perfusion first technique, for chronic dissection with dilatation of the aorta. Using a "side-ways-tau shaped" incision, this technique allows single-staged repair, full-time antegrade perfusion, less possibility of mesenteric malperfusion and cerebral embolism.     

Surgical management of a left main stem coronary artery aneurysm

Left main stem aneurysms are rarely described and the optimal treatment is controversially discussed. A majority of these patients undergo medical treatment with antiplatelet or anticoagulation drugs. Surgery is just recommended in symptomatic patients or when there is the risk of thromboembolic events or rupture. We report on a 51-year-old patient suffering from intermittent angina pectoris in whom an aneurysm of the left main stem was diagnosed by coronary angiography. The patient underwent successful surgical management with aneurysm closure and reconstruction of the left main stem by a segment of the great saphenous vein. This report summarizes the main treatment options for left main stem aneurysms and discusses the role of cardiac surgery for this rare disease.     

Reducing intraoperative myocardial acidosis by continuous cardioplegic perfusion via the coronary sinus

Continuous retrograde coronary sinus perfusion (RCSP) can deliver cardioplegic solution homogeneously to the myocardium via the disease-free venous system. However, administration of cardioplegic solution through the coronary venous system necessitates low pressure infusion which may limit the rate of cardioplegic delivery. In addition, infusion of the solution at low flow rates may not prevent the development of myocardial acidosis during arrest. To determine if RCSP is capable of limiting intraoperative myocardial acidosis, open-chest pigs, monitored by intramyocardial pH probes, underwent cardioplegic arrest with a single dose aortic root infusion followed by a 45-min period of no RCSP (Group 1), RCSP of 25 mEq/liter bicarbonate-buffered cardioplegic solution (Group 2), RCSP of blood-buffered cardioplegic solution (Group 3), and RCSP of histidine-buffered cardioplegic solution (Group 4). There were no significant differences between the groups with respect to baseline pH, with a range of 7.27 to 7.32. At the end of the 45-min arrest period, Group 2 had a statistically higher pH, 7.06 +/- 0.08, compared to Group 1, 6.74 +/- 0.08 (P less than 0.05). Hearts in Groups 3 and 4 demonstrated preservation of preischemic pH levels after 45 min of arrest, 7.29 +/- 0.07 and 7.37 +/- 0.10, respectively, significantly higher than either Group 1 or 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative study of brain protection in ascending aorta replacement for acute type A aortic dissection: retrograde cerebral perfusion versus selective antegrade cerebral perfusion

Objectives

Postoperative disorders of the central nervous system remain a major problem in thoracic aortic surgery. Both retrograde cerebral perfusion and selective antegrade cerebral perfusion have become established techniques for cerebral circulatory management. In this study, we compared neurologic outcomes and mortality between retrograde cerebral perfusion and antegrade selective cerebral perfusion in patients with acute type A aortic dissection who underwent emergency ascending aorta replacement.

Methods

Between January 2003 and April 2011, a total of 203 patients with acute type A aortic dissection underwent emergency ascending aorta replacement in our hospital. We performed retrograde cerebral perfusion in 109 patients before 2006, and then mainly performed antegrade selective cerebral perfusion in 94 patients from 2006 onward.

Results

Cardiopulmonary bypass time and systemic circulatory arrest time were significantly longer in the antegrade selective cerebral perfusion group (p?=?0.04, p?<?0.001, respectively). The incidences of transient brain dysfunction and permanent brain dysfunction after surgery did not differ significantly between the groups. There were also no differences between the groups in other intraoperative variables, such as aortic cross-clamp time and the lowest rectal temperature, or in operative outcomes, including postoperative intensive-care-unit stay, mean peak amylase, and lipase levels until postoperative day 7, and 30-day mortality.

Conclusion

Both retrograde cerebral perfusion and antegrade selective cerebral perfusion were associated with acceptable levels of postoperative neurologic deficits, mortality, and morbidity. Either of these techniques for brain protection can be used selectively, based on a comprehensive assessment of general condition, in patients undergoing surgery for acute type A aortic dissection.     

Acute type A aortic dissection: retrograde perfusion with left superior vena cava

Retrograde cerebral perfusion with hypothermic circulatory arrest confers additional cerebral protection during repair of type A aortic dissection. We present a 42-year-old man with acute type A aortic dissection and a persistent, left superior vena cava. Cannulation of the right and left superior vena cava is used for retrograde perfusion of both hemispheres with bilateral monitoring of electroencephalogram and somatosensory-evoked potentials during and after the hypothermic circulatory arrest interval.     

Resection of a giant left main stem coronary artery aneurysm.

A 2 cm in diameter aneurysm of the left main stem was diagnosed in 1979. The aneurysm increased to 10 cm in diameter during 20 years. It was resected and successful bypass surgery was performed. No previous report was found of a giant true aneurysm involving the left main stem.     

Myocardial protection during aortic valve replacement. Selective infusion of cold cardioplegic solution into the left coronary artery

A simple method for hypothermic cardioplegia during aortic valve surgery is described. Cold cardioplegic solution (Ringer's acetate with 16 mEq potassium added) was selectively infused into the left coronary artery after the aorta had been opened. This resulted in an even cooling of the left ventricle with a relatively small amount of cardioplegic solution. Local cooling with "soft ice" was then initiated and the heart isolated from its warmer surroundings with the aid of a specially designed pad of compressed plastic foam. Thus, the left ventricular temperature could be kept below 20 degrees C for more than one hour. One hundred and three (103) patients were operated on with this method during a one-year-period. Only one patient died (1%). There were few early and/or late complications. Postoperative heart function was excellent in 23 patients subjected to a special study. Peak aortic pressure during the first 16 postoperative hours was 130 (+/- 22) mmHg, mean left atrial pressure 12 (+/- 2) mmHg, mean right atrial pressure 10 (+/- 2) mmHg and all patients were in sinus rhythm. There was a brief and limited release of myocardial enzymes postoperatively, indicating slight intra-operative myocardial damage. Apart from the cardioplegic technique, there are certain factors of importance for the efficacy of myocardial protection during aortic valve replacement. Among them may be mentioned avoidance of ventricular fibrillation, gentle reperfusion after release of the aortic cross-clamping, avoidance of left ventricular distension and administration of calcium intravenously before termination of bypass.