[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.

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.

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.

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.

[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.

Effect on treadmill exercise capacity, myocardial ischemia, and left ventricular function as a result of repeated whole-body periodic acceleration with heparin pretreatment in patients with angina pectoris and mild left ventricular dysfunction.

Whole-body periodic acceleration (WBPA) has been developed as a passive exercise device capable of improving endothelial function by applying pulsatile shear stress to vascular endothelium. We hypothesized that treatment with WBPA improves exercise capacity, myocardial ischemia, and left ventricular (LV) function because of increased coronary and peripheral vasodilatory reserves in patients with angina. Twenty-six patients with angina who were not indicated for percutaneous coronary intervention and/or coronary artery bypass grafting were randomly assigned to remain sedentary (sedentary group) or undergo 20 sessions of WBPA with the motion platform for 4 weeks (WBPA group) in addition to conventional medical treatment. WBPA was applied at 2 to 3 Hz and approximately ±2.2 m/s² for 45 minutes. We repeated the symptom-limited treadmill exercise test and adenosine sestamibi myocardial scintigraphy. In the WBPA group, the exercise time until 0.1-mV ST-segment depression increased by 53% (p <0.01) and the double product at 0.1-mV ST-segment depression by 23% (p <0.001). Severity score of myocardial scintigraphy during adenosine infusion decreased from 20 ± 10 to 14 ± 8 (p <0.001) and severity score at rest also decreased from 13 ± 10 to 8 ± 10 (p <0.01). On scintigraphic images at rest, LV end-diastolic volume index decreased by 18% (p <0.01) with an augmentation of LV ejection fraction from 50 ± 16% to 55 ± 16% (p <0.01). In contrast, all studied parameters remained unchanged in the sedentary group. In conclusion, treatment with WBPA for patients with angina ameliorates exercise capacity, myocardial ischemia, and LV function.

Alternative approach for aortic valve replacement: in mediastinal deviation after right lobectomy.

A 71-year-old man on hemodialysis and with a history of right lobectomy was referred for aortic valve replacement. Chest computed tomography revealed counterclockwise rotation of the heart through its longitudinal axis.We approached the aortic valve through median sternotomy. Accordingly, we transected the sternum at the level of the 3rd intercostal space and extended the skin incision approximately 2 inches perpendicular to the midline. After partial transection of the sternum, 3 spreaders were placed: the 1st, in the upper sternum; the 2nd, in the lower sternum; and the 3rd, between the ribs. These devices yielded excellent exposure of the ascending aorta. In addition, the relatively central shift of the ascending aorta contributed to the exposure of the right atrium and the right upper pulmonary vein. Subsequently, aortic valve replacement was performed in the usual fashion, and the patient experienced no postoperative respiratory complications. Aortic valve surgery with T-shaped sternotomy and without thoracotomy is an alternative technique in a patient who has a secondary deviation after lobectomy.

[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.

Enhanced angiogenesis by gelatin hydrogels incorporating basic fibroblast growth factor in rabbit model of hind limb ischemia.

Recently we have developed new sustained release system of basic fibroblast growth factor (bFGF) using gelatin hydrogel as a carrier. Using this system, we examined the effect of topical sustained release of bFGF on angiogenesis and tissue blood perfusion in a rabbit model of hind limb ischemia. Thirty-two rabbits underwent excision of right femoral artery under general anesthesia. Two weeks later the rabbits were randomized into four groups (n = 8 each): no treatment, intramuscular injection of gelatin hydrogel alone, and intramuscular injection of gelatin hydrogel incorporating 30 microg and 100 microg of bFGF. Four weeks after each treatment, selective angiography, tissue blood flowmetry using laser Doppler perfusion imaging, and histological examination of thigh muscle were performed. In groups treated with bFGF incorporating gelatin hydrogel, tissue blood flow, number of arterioles, and vascular density were significantly increased in a dose-dependent manner 4 weeks after the treatment. Serum concentrations of bFGF and vascular endothelial growth factor were not elevated 4 weeks after the treatment. In conclusion, sustained release of bFGF using gelatin hydrogel augmented angiogenesis and improved tissue blood flow after excision of the femoral artery.

[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.

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.

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.

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.

Therapeutic angiogenesis by the controlled release of basic fibroblast growth factor for ischemic limb and heart injury: toward safety and minimal invasiveness.

We review our studies on therapeutic angiogenesis using basic fibroblast growth factor (bFGF) released in a controlled manner from biodegradable gelatin hydrogel (GH). The bFGF-GH was intramuscularly injected in rabbits with limb ischemia. The group treated with bFGF showed an increase in tissue blood flow under laser Doppler imaging and histology showed a greater vascular density compared with controls. Also, bFGF-GH was subepicardially injected into old heart infarcts in rats. In the group treated with bFGF, improved left ventricular function was shown by echocardiography and cardiac catheterization, increased regional blood flow in the peri-infarct area was detected by pinhole single-photon emission computed tomography using (201)Tl, and increased vascular density was demonstrated by histology. In rabbits with acute myocardial infarction, the heart was wrapped with the omentum (including the gastroepiploic artery) and a bFGF-GH sheet was applied. Postoperative assessment revealed rich communication from the gastroepiploic artery to the coronary artery and improved cardiac function. The controlled release of bFGF was effective for both limb and heart ischemia and is considered to be suitable for clinical use because its application in animals was feasible and safe with minimal invasiveness.

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.

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.

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.