[Valve-sparing Replacement in Patients with Aortic Root Dilatation].

Valve-sparing root replacement is increasingly used to overcome drawbacks associated with valvular prostheses. In our institution, 7 patients underwent valve-sparing root replacement from August 2016 to July 2017. The mean age was 45 years (range, 14~69 years). Three patients had Marfan syndrome and 1 had Loeys-Dietz syndrome with acute aortic dissection. All patients underwent surgery with reimplantation technique using a Valsalva graft. Two patients required repair of aortic valve leaflet prolapse. All patients had an excellent clinical course, with mild or no aortic regurgitation and a decrease in end-diastolic volume on echocardiography. These results support the continued use of valve-sparing root replacement in selected patients.

Five-Year Clinical Outcome of Asymptomatic vs. Symptomatic Severe Aortic Stenosis After Aortic Valve Replacement.

BACKGROUND: There is discordance regarding the effect of symptom status before aortic valve replacement (AVR) on long-term outcome after AVR in severe aortic stenosis (AS).Methods and Results:The CURRENT AS registry is a multicenter retrospective registry enrolling 3,815 consecutive patients with severe AS. Among 1,196 patients managed with the initial AVR strategy, long-term clinical outcomes were compared between the symptomatic patients (n=905), and asymptomatic patients (n=291). Median follow-up interval was 1337 days with a 91% follow-up rate at 2 years. AVR was performed in 886 patients (98%) in the symptomatic group and in 287 patients (99%) in the asymptomatic group. Symptomatic patients were older and more often had comorbidities than asymptomatic patients with similar echocardiographic AS severity. The cumulative 5-year incidences of all-cause death and heart failure (HF) hospitalization were significantly higher in symptomatic patients than in asymptomatic patients (25.6% vs. 15.4%, P=0.001, and 14.2% vs. 3.8%, P<0.001, respectively). On landmark analysis at 30 days after AVR, the differences in mortality and HF hospitalization between the 2 groups were mainly observed beyond 30 days. CONCLUSIONS: When managed with the initial AVR strategy, the long-term outcomes of symptomatic severe AS were worse than those of asymptomatic severe AS. Early AVR strategy might be recommended in some selected asymptomatic severe AS patients with reasonable operative risk.

[Successful treatment of the intracranial hemorrhage after the cardiac surgery for infective endocarditis].

We report an extremely rare case of a successful treatment of the intracranial hemorrhage after the cardiac surgery for infective endocarditis(IE). A 34-year-old woman was admitted to our hospital with a diagnosis of active IE due to Staphylococcus aureus, complicated with cerebral infarctions. Preoperative echocardiography showed mobile vegetations on both leaflets of the mitral valve with 15 and 6 mm diameters. Mitral valve repair was performed on hospital day 10. There were mobile vegetations on the A2 and P3. Five days after the cardiac surgery, brain magnetic resonance imaging(MRI) and angiography demonstrated intracranial hemorrhage due to the rupture of the intracranial aneurysm, which was urgently clipped. No neurological sequel has been noted since the successful treatment.

Growing Renal Vein Aneurysm Treated by Endovascular Repair: A Case Report and Literature Review.

Renal vein aneurysm (RVA) is extremely rare and often asymptomatic, disclosed only incidentally on diagnostic imaging modalities such as computed tomography and ultrasonography. Management is often just watchful follow-up, but some patients require intervention. We present the case of a 74-year-old man complaining of lower back pain in whom a 53-mm RVA was identified. He underwent successful endovascular repair using Amplatzer vascular plugs. The aneurysm had completely resolved by 12 months. Endovascular treatment of a primary RVA does not seem to have been reported previously. This is a milestone case in the management of RVA.

[Clinical analysis of precaution against atrial fibrillation following cardiac surgery: landiolol or amiodarone?].

Atrial fibrillation following cardiac surgery remains as a most common complication. Tachycardia with atrial fibrillation just after the operation could lead to cardiac deterioration. Although we have to control tachycardia, we often have great difficulties in managing these arrhythmias. Many reports have showed landiolol, ultra short-acting beta1 blocker, and amiodarone were effective against postoperative atrial fibrillation. However there has been no report on comparison between these 2 drugs. As excessively sympathetic activity might cause atrial fibrillation, landiolol was introduced into our therapy concomitant with the sedative. Our investigation confirmed that both landiolol and amiodarone were effective in preventing atrial fibrillation, and that the timing of transition from intravenous administration to oral intake was acceptable. When landiolol was administered, enough attention should be paid to the patients whose left ventricular function was low. The patients in whom atrial fibrillation occurred under landiolol therapy showed tendency of lower heart rate in comparison with the patients under amiodarone therapy.

Impact of the left ventricular mass index on the outcomes of severe aortic stenosis.

OBJECTIVE: To elucidate the factors associated with high left ventricular mass index (LVMI) and to test the hypothesis that high LVMI is associated with worse outcome in severe aortic stenosis (AS). METHODS: We analysed 3282 patients with LVMI data in a retrospective multicentre registry enrolling consecutive patients with severe AS in Japan. The management strategy, conservative or initial aortic valve replacement (AVR), was decided by the attending physician. High LVMI was defined as LVMI >115 g/m2 for males and >95 g/m2 for females. We compared the risk between normal and high LVMI in the primary outcome measures compromising aortic valve-related death and heart failure hospitalisation. RESULTS: Age was mean 77 (SD 9.6) years and peak aortic jet velocity (Vmax) was 4.1 (0.9) m/s. The factors associated with high LVMI (n=2374) included female, body mass index ≥22, absence of dyslipidemia, left ventricular ejection fraction <50%, Vmax ≥4 m/s, regurgitant valvular disease, hypertension, anaemia and end-stage renal disease. In the conservative management cohort (normal LVMI: n=691, high LVMI: n=1480), the excess adjusted 5-year risk of high LVMI was significant (HR: 1.53, 95% CI 1.26 to 1.85, p<0.001). In the initial AVR cohort (normal LVMI: n=217, high LVMI: n=894), the risk did not differ significantly between the two groups (HR: 0.96, 95% CI 0.60 to 1.55, p=0.88). There was a significant interaction between the initial treatment strategy and the risk of high LVMI (p=0.016). CONCLUSIONS: The deleterious impact of high LVMI on outcome was observed in patients managed conservatively, but not observed in patients managed with initial AVR. TRIAL REGISTRATION NUMBER: UMIN000012140; Post-results.

Saphenous vein graft rupture eighteen years after coronary artery bypass grafting.

Delayed saphenous vein graft (SVG) rupture following coronary artery bypass graft (CABG) is an unusual but potentially fatal complication. Herein we report a case of SVG rupture 18 years after CABG. A 75-year-old man had undergone a CABG with SVG in 1987 at another institution. In 2004 the patient developed angina and underwent re-CABG with arterial conduits in our hospital. On the preoperative cineangiogram, the SVG to the right coronary artery (RCA) was irregularly dilated, yet still providing flow to the distal RCA. In 2005 he was readmitted to our hospital for abdominal pain. Chest computed tomography revealed a huge round mass adjacent to the heart. Cineangiogram showed leakage of the contrast in the midportion of the SVG. At operation, graft rupture was evident and repaired under cardiopulmonary bypass. Although cardiac function was well maintained, after the surgery he developed ischemic colitis and died of multiple organ failure on the 17th postoperative day.

[Calcified amorphous tumors with excision in hemodialysis patients: report of 2 cases].

We report 2 cases of calcified amorphous tumor (CAT) in hemodialysis patients. Case 1 is a 68-year-old man who had received hemodialysis for 11 years due to diabetic nephropathy with renal failure. He was admitted because of shortness of breath. After appropriate diagnostic testing, we found a 7 mm movable tumor on the side of the left atrium causing stenosis at the base of the left anterior descending artery (LAD). We suspected this to be a myxoma. We performed a myxomectomy and coronary artery bypass grafting (CABG). The tumor had a stalk and hemogenesis on the surface. Case 2 is a 63-year-old man who had received continuous ambulatory peritoneal hemodialysis for 18 months due to diabetic nephropathy with renal failure. He was admitted because of subjective complaints of chest compression and shortness of breath. Ultrasound cardiography revealed 16 mm tumor on the posterior mitral valve leaflet with mild mitral regurgitation. We removed the tumor and placed a mitral valve prosthesis. Grossly the tumor was encapsulated with endocardium. On pathological examination, both tumors were CATs. CAT is a lesion characterized by calcified fibrin deposits. Preoperative diagnosis of these tumors is difficult. While many surgeons elect to conservatively watch these tumors among dialysis patients, when they are movable, there is a risk of embolism and we should remove the tumor early.

Mechanical ventilatory assistance may reduce dyspnea during walking especially in patients with impaired cardiopulmonary function early after cardiovascular surgery.

BACKGROUND: To determine which patients effectively respond to ventilatory assistance (VA) and to examine the factors influencing patient response in patients who underwent cardiovascular (CV) surgery. METHODS: We conducted the first walking session after surgery either with or without VA in a randomized order. The patients walked with 3cmH2O of inspiratory pressure support. We measured dyspnea and leg fatigue during initial walking either with or without VA by using a modified Borg scale. Ventilatory parameters were measured by mechanical ventilation before and immediately after walking. Lung function and maximal inspiratory pressure (MIP) were measured and chest radiographs were analyzed by the same cardiac surgeon on the same day as walking. RESULTS: From the total of 74 patients who underwent CV surgery, 56 patients were successively enrolled in the study. Thirty-five out of 56 patients had dyspnea and 18 patients (30% of the total patients) effectively responded to VA (responders). Minute ventilation/estimated maximum voluntary ventilation immediately after walking significantly decreased with VA, and MIP was lower in responders than in non-responders after surgery. The responders revealed greater pulmonary edema scores than non-responders. CONCLUSIONS: The findings of the present study suggest that VA may possibly facilitate successful mobilization early after CV surgery, especially in patients with impaired cardiopulmonary function.

Incidence and Predictors of Catheterization-Related Cerebral Infarction on Diffusion-Weighted Magnetic Resonance Imaging.

Introduction. The aim of this study was to examine the incidence and risk factors of catheterization-related CI in the contemporary era, using diffusion-weighted magnetic resonance imaging. Methods. We retrospectively analyzed consecutive 84 patients who underwent MRI (magnetic resonance imaging) after 2.81 ± 2.4 days (mean ± SD) of catheterization via aortic arch. We categorized the patients by the presence or absence of acute CI determined by diffusion-weighted MRI and analyzed the incidence and predictors. Results. Of 84 patients that underwent MRI after catheterization, acute CI was determined in 27 (32.1%) patients. In univariate analysis, dyslipidemia, age, coronary artery disease, antiplatelet agents, number of catheters used, urgent settings, and interventional procedures were significantly different. Multivariate analysis revealed dyslipidemia (odds ratio [OR], 4.46; 95% confidence interval [CI], 1.41-16.03; p = 0.01), higher age (OR, 1.09; 95% CI, 1.007-1.19; p = 0.03), and the number of catheters used (OR, 2.21; 95% CI, 1.21-4.36; p = 0.01) as independent predictors of the incidence of catheterization-related acute CI. Conclusions. Dyslipidemia, higher age, and number of catheters used were independent predictors for acute CI after catheterization. These findings imply that managing dyslipidemia and comprehensive planning to minimize the numbers of catheters are important.

Maintenance of pulmonary vasculature tone by blood derived from the inferior vena cava in a rabbit model of cavopulmonary shunt.

INTRODUCTION: After cavopulmonary shunt in which the superior vena cava is anastomosed to the right pulmonary artery, the right lung is in a unique condition without flow pulsatility and hepatic venous effluent. In a previous study, we reported that hypoxic pulmonary vasoconstriction disappeared in the pulmonary circulation after cavopulmonary shunt. In this study, however, to investigate the influence of pulsatility and hepatic venous effluent on hypoxic pulmonary vasoconstriction in the pulmonary circulation, we developed an alternative cavopulmonary shunt rabbit model that included hepatic venous effluent in the pulmonary circulation and reduced the pulsatility of the pulmonary arterial blood flow. We then observed the physiologic characteristics of the peripheral pulmonary artery after cavopulmonary shunt, specifically the disappearance of hypoxic pulmonary vasoconstriction. METHODS: Sixteen Japanese white rabbits (12-16 weeks old) were used in this study. With general anesthesia, a cavopulmonary shunt was established by anastomosing the right superior vena cava to the right pulmonary artery in an end-to-side fashion. Of the 16 rabbits for the study, the proximal right pulmonary artery was completely ligated in 5 (atresia group) and partially ligated in 6 (stenosis group). Sham operation was performed in the remaining 5 rabbits. Two weeks later, we analyzed the response of the pulmonary artery (which was divided into three categories: segmental, lobular, and acinar level artery) to hypoxia (8% oxygen inhalation) with a specially designed video radiographic system. Morphometric analysis of the resistance pulmonary artery was done in each group after angiography. RESULTS: Mean pressure and pulse pressure in the right pulmonary artery were not significantly different between the atresia and stenosis groups. The mean pulmonary artery pressures in the atresia and stenosis groups were 8 and 11 mm Hg, respectively. However, the pulse pressure was less than 2 mm Hg in both groups. The baseline internal diameter of the resistance pulmonary artery of the atresia group was significantly different from those of the stenosis and sham groups. In the atresia group, the resistance pulmonary arteries did not respond to hypoxia. In contrast, significant constriction (as assessed by percentage change of internal diameter of the resistance pulmonary arteries in the acinar and lobular level arteries) was observed in the pulmonary arteries of the sham and stenosis groups (atresia vs stenosis vs sham 0.4% vs - 19.0% vs - 18.8%, P = .01). In our morphometric study, we observed vasodilation of the resistance pulmonary artery with a thinner medial layer in the atresia group, consistent with the result of microangiography. CONCLUSION: We developed a cavopulmonary shunt rabbit model in which the inferior vena caval blood was derived from the right ventricle. Hypoxic pulmonary vasoconstriction was maintained in the model with the blood flow from the right ventricle. When the blood flow was not maintained, however, hypoxic pulmonary vasoconstriction disappeared. This phenomenon strongly suggests that a substance in hepatic venous effluent partially regulates the physiological pulmonary vascular function in the rabbit lung.

Dissecting aortic aneurysm in a renal transplant recipient.

There have been few reports of surgical repair of acute aortic dissection in renal transplant recipients. The incidence, operative risk, or perioperative management of aortic dissection with functioning allografts remains unknown. Herein we report our experience in successful treatment of type I dissecting aortic aneurysm in a renal transplant patient. A 35-year-old man was admitted to our hospital complaining of severe chest pain. He had undergone a living renal transplant from his mother for chronic renal failure caused by immunoglobulin A nephropathy 11 years prior to admission. An immunosuppressive regimen had been maintained continuously. Preoperative chest computed tomography demonstrated a thoracic dissecting aortic aneurysm (DeBakey classification type I). An emergent graft replacement for the ascending aorta was placed under circulatory arrest. Although continuous hemodiafiltration was required postoperatively because of deteriorated renal function, he recovered uneventfully and his renal function returned to preoperative values. He was discharged on postoperative day 26 without any complications.

A propensity score-matching analysis of transthoracic echocardiography and abdominal ultrasonography for the detection of abdominal aortic aneurysms.

INTRODUCTION: We previously reported that the prevalence of abdominal aortic aneurysms (AAAs) was higher in patients undergoing scheduled transthoracic echocardiography (TTE) than in patients undergoing abdominal ultrasonography (AUS); however, intergroup patient backgrounds differed significantly in that report. PURPOSE: We tested the hypothesis that TTE could detect AAA as effectively as AUS. DESIGN: A propensity score-matching analysis of a cross-sectional study was adopted as the design for this study. METHODS: We enrolled 7,619 and 15,433 patients scheduled to undergo TTE with additional evaluation of abdominal aorta at the end of the routine study and AUS, respectively, from 2009 to 2010 in our hospital, as reported. A propensity score for profiles of patients who underwent TTE or AUS was developed to adjust for potential confounding bias. Consequently, 4,388 patients in each group were matched for analyses. RESULTS: In propensity-matched patients, AAA was detected in 59 patients of the TTE group and in 48 patients of the AUS group; the prevalence of AAA detection did not differ significantly between TTE and AUS groups (P = 0.331). Positive associations were observed between AAA detection and male sex (adjusted odds ratio [OR]: 3.25; 95% confidence interval [CI], 2.05-5.15; P < 0.001), older age (adjusted OR: 1.029; 95% CI: 1.01-1.04; P < 0.001), and the presence of ischemic heart disease (adjusted OR: 1.78; 95% CI: 1.04-3.03; P = 0.033) and hypertension (adjusted OR: 2.16; 95% CI: 1.38-3.37; P = 001). CONCLUSION: TTE detected AAA with comparable efficacy as AUS in propensity-matched groups who underwent scheduled TTE and AUS.

Expression Patterns of miRNA-423-5p in the Serum and Pericardial Fluid in Patients Undergoing Cardiac Surgery.

BACKGROUND: Recently, it has been reported that specific microRNA (miRNA) levels are elevated in serum and can be used as biomarkers in patients with cardiovascular diseases. However, miRNAs expression profiles and their sources in pericardial fluid (PF) are unclear. METHODS AND RESULTS: The purpose of this study was to identify the levels of miRNAs in PF in relation to those in the serum in patients undergoing cardiac surgery. Serum (S) and PF from patients undergoing coronary artery bypass graft (CABG) due to stable angina pectoris (sAP) and unstable AP (uAP) and aortic valve replacement due to aortic stenosis (AS) were analyzed for the detection of miRNAs. We named these samples S-sAP, S-uAP, S-AS, PF-sAP, PF-uAP, and PF-AS, respectively. We first measured the levels of miR-423-5p, which was recognized previously as a biomarker for heart failure. miR-423-5p levels were significantly higher in PF than serum. Although there was no difference in miR-423-5p levels among the PF-AS, PF-sAP, and PF-uAP, its levels were significantly elevated in S-uAP compared with those in S-AS and S-sAP. In order to clarify the source of miR-423-5p in PF, we measured the levels of muscle-enriched miR-133a and vascular-enriched miR-126 and miR-92a in the same samples. miR-133a levels were significantly higher in serum than in PF, and it was elevated in S-uAP compared with S-AS. miR-126 level was significantly increased in serum compared with PF, and the level of miR-92a the similar tendency. miR-423-5p is located in the first intron of NSRP1. There is another miRNA, miR-3184, encoded in the opposite direction in the same region. In vitro experiments indicated that the duplex of miR-423-5p and miR-3184-3p was more resistant to RNase than the duplex of miR-423-5p and miR-133-3p, which may help to stabilize miR-423-5p in the PF. CONCLUSIONS: Our results suggested that miR-423-5p is enriched in PF, and serum miR-423-5p may be associate with uAP. Its expression pattern was different to that of muscle- and vascular-enriched miRNAs, miR-133a, miR-126, and miR-92a.

Importance of preserving the apex and plication of the base in left ventricular volume reduction surgery.

OBJECTIVE: Volume reduction surgery for dilated cardiomyopathy has not yielded predictable outcomes. The purpose of this study was to clarify the efficacy of modified volume reduction surgery in preserving the left ventricular apex and reducing the left ventricular diameter at the base to maintain fiber continuity. METHODS: Heart failure was induced with propranolol in 12 dogs, and the animals were randomized into 2 groups. In one group the left ventricular wall was plicated between the 2 papillary muscles from the middle to the apex (apex-sacrificing volume reduction surgery, group A, n = 6), and in the other group plication was done from the base to the middle (apex-sparing volume reduction surgery, group B, n = 6). Left ventricular function was then compared between the groups by using echocardiography and sonomicrometry crystals. RESULTS: After volume reduction surgery, the fractional area change at the base in group B was greater than that in group A (40% +/- 3% vs 27% +/- 4%, P =.003). Cardiac output in group B was better than that in group A (2.5 +/- 0.2 vs 1.8 +/- 0.2 L/min, P =.023). Left ventricular end-diastolic pressure in group A was higher than that in group B (16 +/- 2 vs 8 +/- 1 mm Hg, P =.001). Fractional shortening in the long axis, as assessed by means of sonomicrometry, was better in group B than in group A. CONCLUSIONS: Apex-sparing volume reduction surgery capable of maintaining left ventricular fiber continuity provided better left ventricular function in both the systolic and diastolic phases than apex-sacrificing volume reduction surgery in the acute heart failure model. This modification might improve the results of left ventricular volume reduction surgery.

Autosynchronized systolic unloading during left ventricular assist with a centrifugal pump.

OBJECTIVES: The purpose of this study was to investigate how the inflow cannulation site of the left ventricular assist system with a centrifugal pump would influence cardiac function on failing heart models. METHODS: In 10 sheep, a left ventricular assist system was instituted by an outflow cannula in the descending aorta, two inflow cannulas in the left atrium and the left ventricle, and connecting those cannulas to a magnetically suspended centrifugal pump. A conductance catheter and a tipped micromanometer for monitoring the pressure-volume loop were also inserted into the left ventricle. Myocardial oxygen consumption was directly measured. Heart failure was induced by injection of microspheres into the left main coronary artery. The assist rate was varied from 0% to 100% at each inflow cannulation site. RESULTS: The pump flow with left ventricular cannulation increased during the systolic phase and decreased during the diastolic phase, whereas it was constant with left atrial cannulation. Ejection fraction with left atrial cannulation decreased as the assist rate increased, whereas that with left ventricular cannulation was maintained up to 75% assist. The external work with left atrial cannulation decreased gradually as the assist rate increased, whereas the external work with left ventricular cannulation did not decrease until the assist rate reached 75%. The myocardial oxygen consumption in both cannulations decreased proportionally as the assist rate increased; they were significantly less with left ventricular cannulation at the 100% assist rate than with left atrial cannulation. CONCLUSION: Left ventricular cannulation during left ventricular assistance maintains ejection fraction and effectively reduces oxygen consumption.

Hypoxic pulmonary vasoconstriction disappears in a rabbit model of cavopulmonary shunt.

BACKGROUND: Cavopulmonary shunt is widely known as an interim staging procedure in patients with single-ventricle physiology. However, the physiologic characteristics of the pulmonary arterial system after cavopulmonary shunt are not clearly understood. In this article, we developed a rabbit cavopulmonary shunt model and studied the morphologic changes and physiologic characteristics (namely, hypoxic pulmonary vasoconstriction) of pulmonary arteries after cavopulmonary shunt. METHODS: Male Japanese white rabbits aged 12 to 16 weeks were used for the study. In 5 rabbits, the superior vena cava was anastomosed to the right pulmonary artery in an end-to-side fashion, followed by a proximal side ligation of the right pulmonary artery (cavopulmonary shunt group). In 4 rabbits, the superior vena cava and the right pulmonary artery were dissected and clamped for 10 minutes without making a cavopulmonary shunt (sham group). Two weeks after the operation, we then measured the internal diameter of the acinar (internal diameter, 164 +/- 7 microm), the lobular (305 +/- 13 microm), and the segmental (669 +/- 16 microm) pulmonary arteries in both controlled and hypoxic conditions by using a specially designed x-ray television system. Also, morphometric measurements were made in the pulmonary arteries around the terminal bronchioles. RESULTS: Two weeks after the operation, the arterial oxygen tension under room air conditions was significantly lower in the cavopulmonary shunt group than in the sham group (68.2 +/- 2.2 mm Hg vs 91.1 +/- 1.9 mm Hg; P =.01). The baseline internal diameters in the acinar and the lobular (resistance), but not the segmental (conduit), pulmonary arteries on the anastomosed side of the cavopulmonary shunt group were significantly larger than those of pulmonary arteries on the nonanastomosed side of the cavopulmonary shunt group and the sham group. Moreover, the pulmonary arteries on the anastomosed side of the cavopulmonary shunt group did not respond to hypoxia, whereas those on the nonanastomosed side of the cavopulmonary shunt and sham groups did have local internal diameter reductions in the acinar and lobular arteries (-1.1% +/- 1.0% in the anastomosed side vs -17.7% +/- 3.5% in the nonanastomosed side vs -20.9% +/- 6.1% in the sham group; P =.03). In the morphometric studies, the internal diameter of the pulmonary artery accompanying the terminal bronchiole in the anastomosed side of the cavopulmonary shunt group was significantly larger, and the ratio of medial thickness relative to the outer diameter was smaller compared with ratios in the nonanastomosed side of the cavopulmonary shunt group and the sham group. CONCLUSIONS: We developed a rabbit cavopulmonary shunt model. In the anastomosed side of the cavopulmonary shunt group, the peripheral pulmonary arteries, which contributed greatly in regulating the pulmonary vascular resistance, had a local reduction in the basal vascular tone and no hypoxic vasoconstriction 2 weeks after the operation.

Development of biologic coronary artery bypass grafting in a rabbit model: revival of a classic concept with modern biotechnology.

OBJECTIVE: We have developed a technique for biologic coronary artery bypass grafting, which is a revival of a classic concept with modern biotechnology. METHODS: Acute myocardial infarction was created by ligating the major branch of the circumflex artery in rabbits. Animals were divided into four groups: a nontreated group (group N), a group in which omentum was used to wrap the infarcted area (group G), a group in which a gelatin hydrogel sheet incorporating 100 microg basic fibroblast growth factor was placed over the infarcted area (group F), and a group in which the infarcted area was similarly treated with basic fibroblast growth factor followed by omental wrapping (group FG). Cardiac function was subsequently assessed by echocardiography. Postmortem angiography through the gastroepiploic artery was done in groups G and FG. Infarct size and arteriolar density were evaluated. RESULTS: Group FG showed a better fractional area change than did the other groups (group N P <.001, group G P =.002, group F P <.001). Angiography revealed that communication from the gastroepiploic artery to the coronary artery was created through a rich bed of neovascularization in all 7 animals of group FG, whereas poor collaterals were recognized in only 2 of 7 animals in group G. Infarct size was reduced to a greater extent in group FG than in groups F, G, and N (10% +/- 3%, 16% +/- 5%, 19% +/- 7%, 23% +/- 2%, respectively, group F P =.04, groups G and N P <.01). The number of arterioles 20 to 100 microm in diameter was increased to a greater extent in group FG than in groups F, G, and N (23 +/- 5 arterioles/mm(2), 14 +/- 3 arterioles/mm(2), 10 +/- 1 arterioles/mm(2), 4 +/- 2 arterioles/mm(2), respectively), with the differences being significant. CONCLUSIONS: These results show that bypass from the gastroepiploic artery to coronary arteries can be achieved without surgical anastomosis through slow release of basic fibroblast growth factor in this rabbit acute myocardial infarction model. This new revascularization concept, biologic coronary artery bypass grafting, could be applicable for revascularizing many tiny coronary vessels in patients who are difficult to treat with conventional surgery or catheter intervention.

Visualization of intramuscular left anterior descending coronary arteries during off-pump bypass surgery.

In off-pump coronary artery bypass surgery, an appropriate method for intraoperative evaluation of grafts and vessels has been awaited. We report the usefulness of a 15-MHz linear transducer for this purpose. A 15-MHz linear transducer with a SONOS 5500 (Philips Medical Systems, Best, Netherlands) was applied epicardially in off-pump coronary artery bypass surgery patients. Vascular anatomy was easily discerned when the transducer was applied in an appropriate way. In 6 patients, intramuscular coronary arteries were easily detected, and in all of these patients, anastomoses were successful. The shapes of the anastomoses were very clearly shown, and the flow and its phase in the bypass graft or coronary artery were measured with synchronization of electrocardiograms in all patients. The total left internal thoracic artery (LITA) flow (28.4 +/- 6.8 mL/s) and the pattern of the flow was dominantly diastolic in all patients. The 15-MHz linear transducer system (Philips) is very useful for detecting intramuscular left anterior descending coronary arteries and may become one of the standard tools for intraoperative evaluation in off-pump coronary artery bypass surgery.

Pharmacological assessment of composite arterial conduits using angiography early in the postoperative period.

OBJECTIVES: Muscular arteries are vulnerable to vasospasm unlike elastic arteries. Having developed experimental models of composite arterial grafts, we assessed and compared the responses of the grafts with different pharmacological agents using angiography early in the postoperative period. SUBJECTS AND METHODS: We harvested the internal thoracic artery (ITA) and brachial-median artery (BMA) from 10 sheep. BMA was used as an alternative to the radial artery. Each vessel was assessed histologically and morphologically. Then, a serial composite graft was constructed so that BMA was interposed. On postoperative day one or two, angiography was performed on the composite graft to measure the diameter of each vessel in response to phenylephrine (alpha-adrenergic receptor agonist), nitroglycerin+phenylephrine, and milrinone+phenylephrine. RESULTS: The BMA had a wide media layer which consisted of abundant smooth muscle cells. The combined intima and media were thicker in BMA than in ITA (p<0.01). After injection of phenylephrine, the BMA diameter decreased (2.5+/-0.4 mm to 1.9+/-0.3 mm, p<0.01), while the ITA diameter remained unchanged (3.7+/-0.2 mm to 3.6+/-0.2 mm). Continuous infusion of nitroglycerin or milrinone prevented phenylephrine-induced vasoconstriction of the BMA (p<0.05). CONCLUSIONS: These results suggest that muscular arteries have a more pronounced vasoconstrictive response to alpha-adrenergic receptor agonists than the elastic arteries. To avoid potential decrease in graft flow of muscular artery, it is advisable to use a vasodilator nitroglycerin or milrinone early in the postoperative period.