Early and Late Surgical Outcomes after Geometrical Infarct Exclusion for Post-Infarct Ventricular Septal Perforation

PURPOSE

Ventricular septal perforation (VSP) is a critical complication of acute myocardial infarction. Various surgical procedures for it have been developed; however, surgical outcomes remain unsatisfactory. In 2010, we introduced geometrical infarct exclusion (GIE) as a modification of the Komeda-David technique. This retrospective study compared the surgical outcomes of our geometric infarct exclusion technique to those of other surgical procedures.

METHODS

This study included 38 patients who underwent surgery for VSP. They were divided into patients who underwent GIE (GIE group; n = 17) and those who underwent other procedures (non-GIE group; n = 21). The clinical outcomes of the two groups were compared.

RESULTS

Operation, cardiopulmonary bypass, and cardiac arrest times in the GIE group were significantly longer than those in the non-GIE group (p <0.001). A residual shunt was observed in one patient (5.8%) in the GIE group and eight (38.0%) in the non-GIE group (p = 0.026). No patients in the GIE group required a reoperation for the residual shut, while two patients required it in the non-GIE group (p = 0.492). Operative mortality was insignificantly different between the two groups.

CONCLUSION

Geometric infarct exclusion has a longer procedural time than does other surgical procedures but can reduce the rates of residual shunts and reoperations.

[Coronary Artery Fistula with Aortic Valve Stenosis:Report of a Case]

A coronary artery fistula usually originates in the right coronary artery and often opens into the right ventricle. In approximately 50% of cases with a main pulmonary artery opening, aberrant blood vessels originate from both coronary arteries. Only a few cases of both coronary and bronchial artery-pulmonary artery fistulas have been reported. The patient was an 83-year-old man. Echocardiography showed severe aortic stenosis, while coronary angiography revealed aberrant vessels from both coronary arteries to the pulmonary artery. The right heart catheterization revealed a 26% left-to-right shunt ratio and a pulmonary/body blood flow ratio (Qp/Qs) of 1.36. MDCT scan confirmed that the aberrant vascular plexus originating from both coronary arteries was connected to the bronchial artery. We performed surgery on the patient, replacing the aortic valve and resecting the coronary arteriovenous fistulas. On the 11th postoperative day, the shunt had disappeared, as evidenced by a 1.2% left-toright shunt ratio and a Qp/Qs of the right heart catheterization of 1.02. The patient progressed uneventfully and was discharged on the 25th postoperative day.

[Re-operation with Infarct Exclusion Technique due to Residual Shunt after Extended Sandwich Patch Technique for Postinfarction Ventricular Septal Perforation:Report of a Case]

We report a case in which infarct exclusion technique was used to repair residual shunt after extended sandwich patch technique for postinfarction ventricular septal perforation (VSP). A 76-yearold woman was diagnosed with postinfarction VSP and underwent extended sandwich patch technique through right ventriculotomy on the third day after the onset of VSP. No residual shunt was then observed by intraoperative transesophageal echocardiography, but a slight residual shunt was observed on the 7th day after operation. She had no symptom of cardiac failure, and was followed up. However, the residual shunt worsened, and she developed cardiac failure on the 48th day after the initial operation. An additional operation by infarct exclusion technique was performed. No residual shunt was observed after the additional operation. She has been doing well with no signs of cardiac failure.

[Transmitral Septal Myectomy and Mitral Valve Plasty for Hypertrophic Obstructive Cardiomyopathy Combined with Organic Mitral Regurgitation;Report of a Case]

A 60-year-old man with hypertrophic obstructive cardiomyopathy (HOCM) combined with organic mitral regurgitation underwent transmitral septal myectomy and mitral valve plasty. Although a transaortic septal myectomy (Morrow's procedure) is generally accepted as the standard surgical treatment for HOCM, it may be difficult to perform sufficient septal myectomy for mid-ventricular obstructive hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy (HCM). The transmitral approach with temporary detachment of the anterior mitral leaflet provides a good surgical view in the left ventricle, which allows sufficient septal myectomy from the outflow tract to the apex.

Total arch replacement for the treatment of a giant protruding thrombus in the thoracic aorta derived from an atherosclerotic lesion

A thoracic aortic thrombus is rare. The causes of this condition and the feasible options for its treatment remain controversial. Preventing embolic complications are the most important for the management of thoracic aortic thrombi. Herein, we report a case of a giant protruding thrombus in the thoracic aorta. We suggest total arch replacement (TAR) using an open stent graft (OSG) as a favorable management technique for thoracic aortic thrombi. We also recommend bilateral axillary artery cannulation to prevent cerebral infarction.

Outcomes of cardiovascular surgery for chronic dialysis patients in current Japan

Background

The number of dialysis patients in Japan is rising, with an increasing number requiring cardiovascular surgery.

Methods

We investigated the short- and long-term outcomes in 70 dialysis patients among a total of 1124 who underwent cardiovascular surgery in our hospital between 2004 and 2016. We investigated outcomes following open surgery and identified factors that affected the prognosis. We also compared the long-term survival rate with the survival rate of the Japanese dialysis population.

Results

The long-term survival rate was 70.6%, 51.1%, and 19.2% after 3, 5, and 10 years, respectively. The causes of long-term death were heart disease in 8 patients, cerebrovascular disease in 7, cachexia in 3, infection in 2, and other causes in 3. The freedom from cardiac death was 88.7%, 77.9%, and 54.9% after 3, 5, and 10 years, respectively. Multivariate analysis using Cox’s proportional hazard model showed that a history of atherosclerosis obliterans (hazard ratio 5.4, p = 0.05) and mediastinitis (hazard ratio 10.2, p = 0.03) were risk factors for death in long-term follow-up, and a history of atherosclerosis obliterans was an independent risk factor for cardiac death in long-term follow-up (hazard ratio 5.3, p = 0.01). Five-year survival of the study subjects was comparable to that of the Japanese dialysis population.

Conclusions

The prognosis for dialysis patients after open surgery was equivalent to that of Japanese dialysis patients in general. A high proportion of late postoperative deaths were due to heart disease. Patients with atherosclerosis obliterans had a poor prognosis.

Mortality and morbidity after total aortic arch replacement

BACKGROUND

Total aortic arch replacement is associated with considerable mortality and morbidity. Although operative death is the most extreme adverse clinical end point, postoperative morbidity can also be devastating for survivors.

METHODS

We examined the short-term and long-term outcomes of 146 patients who underwent total aortic arch replacements between September 2003 and September 2011.

RESULTS

The overall in-hospital mortality was 4.8%, and major postoperative morbidity during hospitalization occurred in 29 patients (19.9%). Multivariate analyses demonstrated that risk factors for hospital death were left thoracotomy (odds ratio [OR], 51.92; p=0.01), high preoperative serum creatinine values (OR, 3.88; p=0.02), and intraoperative blood loss (OR, 1.01; p=0.04). Ruptured aorta (OR, 7.13; p=0.02) and previous myocardial infarction (OR, 5.13; p=0.04) were identified as independent risk factors for major postoperative morbidity. The postoperative survival of all patients at 5 years was 76.7%±5%. After hospital discharge, the standardized mortality ratios showed no significant difference between hospital survivors and a comparable Japanese population and were 1.09 (p=0.41) among patients without major morbidity and 1.82 (p=0.12) among those with major morbidity. The development of renal failure requiring hemodialysis increased the risk of long-term death (hazard ratio, 5.59; p=0.03), even among hospital survivors.

CONCLUSIONS

Our approach for total arch replacement resulted in low in-hospital mortality and morbidity. Long-term outcomes are stable in hospital survivors, especially in the absence of a postoperative requirement for dialysis.

Pseudoaneurysm of the ascending aorta 31 years after mitral valve replacement

We describe a rare case of an ascending aortic pseudoaneurysm 31 years after mitral valve replacement with a Björk-Shiley mechanical valve. The aneurysm presumably expanded gradually during the years following surgery. As the valve was functioning normally, it was left in situ while the ascending aorta was replaced. This report provides valuable information regarding the long-term nature of this patient's pseudoaneurysm, and the long-term durability of the Björk-Shiley spherical valve in the mitral position.

Arch translocation and the intra-arch elephant-trunk technique with collared graft for extended chronic dissecting aortic aneurysm

Management of extensive, chronic, dissecting aortic aneurysms after prior repair of the ascending aorta presents a technical challenge for surgeons. A symptomatic 64-year-old patient was admitted for elective surgical repair of an aortic annular dilatation, causing severe aortic regurgitation, and a Crawford type II extended thoracoabdominal aneurysm, 4 years after he underwent primary repair of an acute aortic dissection. The aorta was diffusely dilated, and there were no sites beyond the distal aortic arch where anastomosis could be performed. We successfully performed total aortic replacement with a 2-stage strategy, using an arch translocation technique and an intra-arch elephant-trunk technique.

The effects of mechanical stress on the growth, differentiation, and paracrine factor production of cardiac stem cells

Stem cell therapies have been clinically employed to repair the injured heart, and cardiac stem cells are thought to be one of the most potent stem cell candidates. The beating heart is characterized by dynamic mechanical stresses, which may have a significant impact on stem cell therapy. The purpose of this study is to investigate how mechanical stress affects the growth and differentiation of cardiac stem cells and their release of paracrine factors. In this study, human cardiac stem cells were seeded in a silicon chamber and mechanical stress was then induced by cyclic stretch stimulation (60 cycles/min with 120% elongation). Cells grown in non-stretched silicon chambers were used as controls. Our result revealed that mechanical stretching significantly reduced the total number of surviving cells, decreased Ki-67-positive cells, and increased TUNEL-positive cells in the stretched group 24 hrs after stretching, as compared to the control group. Interestingly, mechanical stretching significantly increased the release of the inflammatory cytokines IL-6 and IL-1β as well as the angiogenic growth factors VEGF and bFGF from the cells in 12 hrs. Furthermore, mechanical stretching significantly reduced the percentage of c-kit-positive stem cells, but increased the expressions of cardiac troponin-I and smooth muscle actin in cells 3 days after stretching. Using a traditional stretching model, we demonstrated that mechanical stress suppressed the growth and proliferation of cardiac stem cells, enhanced their release of inflammatory cytokines and angiogenic factors, and improved their myogenic differentiation. The development of this in vitro approach may help elucidate the complex mechanisms of stem cell therapy for heart failure.

Validation of the JapanSCORE versus the logistic EuroSCORE for predicting operative mortality of cardiovascular surgery in Yamaguchi University Hospital

PURPOSE

Recent studies have shown that the European System for Cardiac Operative Risk Evaluation (Euro-SCORE) is a reliable risk model in cardiac surgery. In Japan, the JapanSCORE has been devised as the Japanese original risk model for cardiovascular surgery. We evaluated the validity of the JapanSCORE, especially in comparison with the logistic EuroSCORE METHODS: We calculated the predicted mortality according to two risk models for 523 consecutive patients who underwent cardiovascular surgery within a 6-year period (July 2003 to June 2009) at Yamaguchi University Hospital. We assessed the scores' validity by calculating the area under the receiver operating characteristics curve (C-index) and by the chi-squared test or Fisher's exact test.

RESULTS

The C-indexes were 0.688 with the logistic EuroSCORE and 0.770 with the JapanSCORE (P = 0.053). Although the difference was not significant, the JapanSCORE tended to be more accurate. The C-indexes limited to isolated coronary artery bypass grafting (CABG) were 0.564 with the logistic EuroSCORE and 0.790 with the JapanSCORE (P = 0.001). The Japan-SCORE was significantly more valid than the logistic EuroSCORE for isolated CABG. The actual mortality was 4.0%; the mean predictive mortality was 5.6% with the JapanSCORE and 15.1% with the logistic Euro-SCORE. The mortality predicted by the JapanSCORE was closer to the observed mortality. There was a significant difference between the observed mortality and the logistic EuroSCORE (P < 0.0001).

CONCLUSION

The JapanSCORE seems to be a more reliable risk model than the logistic EuroSCORE for patients undergoing cardiac or thoracic aortic surgery at Yamaguchi University Hospital.

[Total arch replacement for intrathoracic left subclavian artery aneurysm; report of a case]

A 65-year-old man with left subclavian artery aneurysm, detected by enhanced computed tomography (CT), was referred to our hospital. The CT revealed intrathoracic left subclavian artery aneurysm (maximum diameter, 5 cm) at the takeoff of the aortic arch. Surgery was indicated considering the risks of rupture and embolism. The aneurysm was exposed through median sternotomy. Cardiopulmonary bypass was established with cannulation of the right axillary artery, left femoral artery, superior vena cava (SVC), and inferior vena cava (IVC). Circulatory arrest and isolated cerebral perfusion were achieved at a core temperature of 23 degrees C. Total arch replacement was performed using a 26 mm 4-branched Triplex graft, and the left subclavian artery was reconstructed by branch-left axillary artery bypass. The postoperative course was uneventful. He was discharged on the 22nd postoperative day.

[Early results of surgical repair of ventricular septal rupture]

BACKGROUND AND OBJECTIVE

Ventricular septal rupture (VSR) is a lethal complication of acute myocardial infarction, and its operative results are far from good.

SUBJECTS

Six patients who underwent operations for VSR in our department between 2001 and 2008. All these patients received coronary angiography, which showed 1-vessel disease in 4 patients, 2-vessel disease in 1, and 3-vessel disease in 1. The sites of myocardial infarction were the anteroseptal region in 3 patients and the inferoseptal region in 3.

RESULTS

Infarct exclusion was conducted in the 3 patients with anteroseptal infarction. Of the 3 patients with inferoseptal infarction, 1 underwent infarct exclusion and 2 Daggett operation. The number of in-hospital deaths was 3 (50%). Residual shunts were observed in 3 out of the 4 patients (75%) who had received infarct exclusion. Two of these 3 patients needed reoperation. The 2 patients with inferoseptal infarction who had undergone Daggett operation presented no residual shunts, and could be easily weaned from the cardiopulmonary bypass.

CONCLUSIONS

Because the infarct exclusion method frequently shows residual shunts, its technical modifications are required to improve the operative results. The Daggett method can be considered useful in patients with VSR after inferior myocardial infarction.

Influence of carotid artery stenosis on stroke in patients undergoing off-pump coronary artery bypass grafting

OBJECTIVE

It is well known that the presence of carotid artery stenosis increases the risk of perioperative stroke in patients undergoing cardiac surgery with cardiopulmonary bypass. Although off-pump coronary artery bypass grafting (CABG) can avoid the adverse effects of cardiopulmonary bypass, the influence of carotid artery stenosis on the incidence of stroke in patients undergoing off-pump CABG has not been well clarified.

METHODS

We conducted a retrospective study of 461 patients who underwent elective off-pump CABG after screening for carotid artery stenosis at our institute between September 2004 and May 2007. The incidence and etiologies of stroke were identified. Preoperative screening revealed significant carotid artery stenosis in 49 patients. Clinical results were compared between patients with and without carotid artery stenosis.

RESULTS

Postoperative stroke occurred in two (0.43%) of the 462 study patients, and in-hospital mortality occurred in three (0.65%). Stroke was due to decreased perfusion resulting from hypovolemic shock in one and thrombosis in the other. There was neither stroke nor in-hospital mortality in patients with carotid artery stenosis, although there were two strokes (0.49%) and three in-hospital mortalities (0.73%) in patients without carotid artery stenosis.

CONCLUSIONS

The influence of carotid artery stenosis on the incidence of perioperative stroke may be little in off-pump CABG, especially in patients with moderate carotid artery stenosis.

[Open stent-grafting for saccular aneurysms of the distal arch and descending aorta; report of a case]

We report the utility of an open stent-grafting for saccular aneurysms of the distal arch and descending aorta. A 68-year-old man showed a radiological abnormality on a chest X-ray film. Chest computed tomography (CT) demonstrated saccular aneurysms of the distal arch and descending aorta. Open stent-grafting was performed using a homemade device. The postoperative course was uneventful. Postoperative CT showed satisfactory placement of the endograft, without extravasation. Open stent-grafting was a useful therapeutic procedure in this case of multiple aneurysms.

[Blunt right atrial rupture]

Atrial rupture without other major injury following blunt chest trauma is rare, but carries high mortality rate. Here we report 3 cases of blunt atrial rupture. All patients presented with hypotension and loss of consciousness. Echocardiography and computed tomography (CT) demonstrated pericardial effusion in all cases. All patients underwent surgery with a median sternotomy. Tear of the right atrium was seen in 2 patients, and no remarkable tear was seen in 1 patient. One of the 3 patients underwent surgery using cardiopulmonary bypass because he showed cardiogenic shock. Pericardiocentesis before the operation was not effective. All patients were discharged uneventfully. Echocardiography and CT were useful for diagnosis of cardiac rupture. In most reported cases, the cardiac tear has been repaired without using cardiopulmonary bypass. However, it is difficult to diagnose location of the tear, therefore, the repair became safer using cardiopulmonary bypass for the patients with cardiogenic shock. This article has described the mechanisms and generation of blunt chest trauma lesions.

[Ruptured infected descending aortic aneurysm successfully treated by omentopexy and a rifampicin-soaked vascular prosthesis; report of a case]

A 73-year-old man was admitted for investigation of back pain, blood-stained sputum, and a high fever. Computed tomography (CT) showed a pseudoaneurysm in the descending aorta and intravenous antibiotic therapy was begun immediately after blood had been taken for culture. However, his temperature continued to spike daily, up to 38 degrees C, and his CRP was also elevated. The blood cultures were negative. The aneurysm ruptured and we replaced the descending aorta with a rifampicin (RFP)-soaked vascular prosthesis, and wrapped it with greater omentum. Postoperative antibiotic therapy with vancomycin hydrochloride, RFP, and amikacin sulfate was continued for 8 weeks. The patient recovered uneventfully. Thus, an infected aneurysm was effectively treated with a RFP-soaked vascular prosthesis and omentopexy.

[Left coronary ostial stenosis caused by syphilitic aortitis]

We report 2 cases of cardiovascular disease related to end-stage syphilitic infection, which is now relatively rare. A 49-year-old man (case 1), and a 45-year-old man (case 2) were admitted to our hospital for angina pectoris. Cardiac catheterization showed severe aortic regurgitation and left coronary ostial stenosis. Active syphilis was detected in both cases by routine blood examination on admission. Oral ampicillin was started immediately to treat the syphilis; however, during the course of treatment, acute heart failure developed in both patients. We performed emergency aortic valve replacement and coronary artery bypass grafting. Intraoperatively, the orifice of the left coronary artery was almost occluded, and retrograde perfusion of cardioplegia was needed to induce cardiac arrest. Both patients recovered uneventfully. When treating patients with antibiotics for syphilitic disease, it is important to prepare for the possibility of urgent surgery.

[Strategy for thrombosed type A acute aortic dissection]

The surgical treatment for thrombosed type A aortic dissection is controversial. We treated 15 cases (28.8%) with thrombosed type A acute aortic dissection among 52 cases of all type A acute aortic dissection during past 7 years and 8 months. Nine cases was treated conservatively and 6 cases received emergent operation due to cardiac tamponade, shock, and ulcer-like projection (ULP) in the ascending aorta (> 50 mm). In the group of conservative therapy, 2 cases in which the ascending aorta was enlarged (54, 60 mm), was converted to operation in the acute phase because of further enlargement of ascending aorta and increase of cardiac effusion. The other patients (aortic diameter: 40-46 mm) who received conservative therapy were well controlled by medical therapy in the early and late phase except 1 who died suddenly in the follow-up. There was no mortality and late death in the operated patients. From these results, we conclude that thrombosed type A aortic dissection in which the diameter of ascending aortic aorta is larger than 50 mm, have cardiac tamponade and ULP in the ascending aorta might needs operation.

[Acceleration of aortic regurgitation due to localized aortic dissection; report of a case]

We successfully treated a patient with accelerated aortic regurgitation due to localized aortic dissection with mitral regurgitation causing congestive heart failure. A 58-year-old female, who had suffered from aortic regurgitation for more than 10 years, had acute heart failure due to acceleration of aortic regurgitation. The surgical findings showed prolapse of the aortic valve due to localized dissection in the sinus of Valsalva. We performed a Bentall operation and a mitral valve replacement, with a favorable outcome. The postoperative course was uneventful.

Angiogenesis induced by the injection of peripheral leukocytes and platelets

BACKGROUND

Peripheral leukocytes and platelets (LAPs) contain many kinds of cells with the ability to secrete several growth factors and cytokines. We attempted to induce therapeutic angiogenesis by injecting self-LAPs into a rat ischemic hindlimb model.

MATERIALS AND METHODS

Supernatants from cultured LAPs were used for the endothelial cell (EC) proliferation assay, and LAPs were used in a cornea model to evaluate angiogenic potency. LAPs were injected directly into the male Dark Agouti rat ischemic hindlimb model, after which a microangiogram was done and the capillary/muscle fiber ratio was examined histologically. ELISA revealed the levels of contributing growth factors and cytokines present in the ischemic muscles.

RESULTS

The EC proliferation assay showed that the supernatants of LAPs accelerated proliferation and that the LAPs induced angiogenesis in the cornea model. The microangiograms and histological evaluation revealed that angiogenesis was induced more effectively in the rats injected with LAPs (LAP group) than in the those injected with phosphate-buffered saline (PBS group). The levels of basic fibroblast growth factor (bFGF) in the ischemia, PBS, and LAP groups were significantly increased compared to those in the sham group. The level of interleukin-1beta (IL-1beta) in the LAP group was significantly more elevated than in the other groups.

CONCLUSIONS

The injection of self-LAPs induced angiogenesis in a rat ischemic hindlimb model. Ischemia caused an elevation in the level of bFGF and also in IL-1beta derived from LAPs, which contributed to angiogenesis. This is a novel, yet simple and safe method of inducing therapeutic angiogenesis.

Fatal diffuse atheromatous embolization following endovascular grafting for an abdominal aortic aneurysm: report of a case

A 78-year-old woman with an abdominal aortic aneurysm, 57 mm in diameter, was admitted to our hospital for endovascular grafting. Preoperative computed tomography and angiography showed friable mural thrombus in the suprarenal and infrarenal aorta, and a diagnosis of shaggy aorta was made. Postoperatively, the patient suffered cerebral infarction, and disseminated intravascular coagulopathy with multiple organ failure developed, resulting in early death on the third day after surgery. An autopsy revealed diffuse atheromatous embolization into the celiac, superior mesenteric, bilateral renal, bilateral hypogastric (trash buttock), and peripheral arteries. This case report serves to demonstrate that an abdominal aortic aneurysm with a shaggy aorta in the proximal neck is a contraindication to endovascular grafting, and that predicting the possibility of diffuse atheromatous embolization by detecting a shaggy aorta is the best way to prevent this catastrophic complication.

Autologous bone marrow implantation induced angiogenesis and improved deteriorated exercise capacity in a rat ischemic hindlimb model

BACKGROUND

Bone marrow possesses endothelial progenitor cells that secrete several growth factors and can contribute to the formation of new capillaries. In the present study, we investigated the extent of angiogenesis induced by implantation of autologous bone marrow cells (BMCs) in a rat ischemic hindlimb model and studied whether the increased collateral vessels can improve deteriorated physical function.

MATERIALS AND METHODS

Ischemic hindlimb was created by ligation of the femoral artery and its branches in Dark Agouti (DA) rats. BMCs (1 x 10(7)) were injected percutaneously at six points into the gastrocnemius muscle. To assess angiogenesis, histologic evaluation and microangiography were performed at 2 weeks postligation. Severity of the ischemic insult was evaluated by measuring blood flow in the adductor and gastrocnemius muscles using nonradioactive colored microspheres and by determining the femoral arteriovenous oxygen difference (AVDO(2)) at 2 weeks postligation. Running time on a motor-driven treadmill was used to represent exercise capacity.

RESULTS

The histologic evaluation and microangiogram showed that the implanted BMCs induce angiogenesis. Blood flow to the adductor muscle on the treated side in the bone marrow cell implantation (BMI) group was significantly restored to 77.3 +/- 19.3% of that of the normally perfused limb in comparison to that in control groups (P < 0.05). AVDO(2) in the BMI group significantly decreased when compared with AVDO(2) in control groups. Rats in the BMI group ran approximately 1.5 times longer than rats in control groups at 2 and 4 weeks postligation (P < 0.01).

CONCLUSIONS

Implantation of autologous BMCs induced angiogenesis and improved deteriorated exercise capacity in our rat ischemic hindlimb model.

Spared flow tract within the mural thrombus of an aortic aneurysm: its pathogenesis and clinical importance

The purpose of this case report is to determine the unique pathogenesis of a "spared flow tract" through a thick mural thrombus of an aortic aneurysm mimicking the penetrating or dissecting tract of an impending or acute rupture of an abdominal aortic aneurysm (AAA) and to discuss its clinical importance. Three blood flow tracts (i.e., spared flow tracts) penetrating to aortic major branches (inferior mesenteric arteries in two and left renal artery in one) through thick mural thrombi of three aortic aneurysms were found on thin section spiral CT scans. Histopathological examination revealed that the tracts were formed by thrombi and partially covered with endothelial cells. In conclusion, spared flow tracts may be pathways continuing to the aortic major branches through thick mural thrombi of aortic aneurysms and are spared from thrombogenesis because of relatively high blood flows. Their pathogenesis is definitely different from penetrating or dissecting tracts within mural thrombi of ruptured AAAs. Spared flow tracts should not be misinterpreted as penetrating or dissecting tracts of impending or acute rupture.

[Experimental study of coronary artery anastomosis using VCS clips]

The experiment was intended to test the feasibility of VCS clips for coronary anastomosis during minimally invasive direct coronary artery bypass grafting (MIDCAB). Six dogs were anesthetized under endotracheal intubation and were placed on right lateral position. Three 10.5-mm ports were placed on the left lateral chest wall (3rd, 5th and 7th intercostal space) and the left internal thoracic artery (LITA) was dissected completely from its root to bifurcation under thoracoscope. Chest was opened through the left 6th intercostal space. The anastomotic site of LAD was dissected and was then occluded temporally for 5 minutes to obtain ischemic preconditioning. The anastomosis was performed by the following procedure; horizontal mattress sutures of 8-0 polypropylene were placed on heel, toe and the center of both lateral sides. Two VCS clips (8 in total), 0.9-mm in size, were applied between every two sutures. After the measurement of graft flow, the pedicle was transected and an angiography was done. Graft flow was 12-17 ml/min (mean 14.7 +/- 2.1 ml/min) and cineangiogram showed good patency of LITA and no anastomotic stenosis. VCS clips were supposed to have a potential for facilitating port access coronary artery bypass grafting.