Tetsuya Niino

Influence of Continuous Infusion of Low-Dose Human Atrial Natriuretic Peptide on Renal Function During Cardiac Surgery A Randomized Controlled Study

OBJECTIVES The purpose of this study was to determine the effect of human atrial natriuretic peptide (hANP) in patients who underwent coronary artery bypass grafting (CABG) on renal function. BACKGROUND Acute renal failure after cardiac surgery is associated with high morbidity and mortality. METHODS A total of 504 patients who underwent CABG were divided into 2 groups: 1 group received hANP at 0.02 microg/kg/min from the start of cardiopulmonary bypass (hANP group), and 1 group did not receive hANP (placebo group). Various parameters were measured before and after surgery. RESULTS There was no difference in mortality between the 2 groups, but post-operative complications were less frequent in the hANP group (p = 0.0208). In the hANP group, serum creatinine (Cr) was significantly lower and urinary Cr and Cr clearance were significantly higher from post-operative day 1 to week 1. The maximum post-operative Cr level and percent increase of Cr were significantly lower in the hANP group (p < 0.0001). Patients with Cr exceeding 2.0 mg/dl included 1 in the hANP group and 8 in the placebo group, showing a significant difference (p = 0.0374). Four patients in the placebo group and none in the hANP group required hemodialysis, but the difference was not statistically significant. CONCLUSIONS Continuous infusion of low-dose hANP from the start of cardiopulmonary bypass effectively maintained post-operative renal function. Infusion of hANP prevents early post-operative acute renal failure and helps to achieve safer cardiac surgery. ( CLINICAL TRIAL REGISTRATION NUMBER UMIN000001440).

Results of low-dose human atrial natriuretic peptide infusion in nondialysis patients with chronic kidney disease undergoing coronary artery bypass grafting: the NU-HIT (Nihon University working group study of low-dose HANP Infusion Therapy during cardiac surgery) trial for CKD.

OBJECTIVES The purpose of this comparative study is to prove the efficacy of the human atrial natriuretic peptide (hANP) in patients with chronic kidney disease (CKD) undergoing coronary artery bypass graft surgery (CABG). BACKGROUND CKD is an important risk factor for cardiac surgery. METHODS This was a randomized controlled study of 303 patients with CKD who underwent CABG, and were divided into a group who received carperitide infusion and another group without carperitide. The primary endpoints were: 1) the post-operative dialysis-free rate; and 2) serum creatinine (sCr) and estimated glomerular filtration rate. The secondary endpoints were: 1) the early post-operative outcome; 2) outcome at 1 year post-operatively; 3) the maximum sCr, the rate of increase of sCr, and an increase of sCr by ≥ 0.3 mg/dl compared with the pre-operative value; and 4) ANP and cyclic-guanosine monophosphate levels. RESULTS The post-operative sCr was significantly lower in the hANP group not only in the post-operative acute stage but also in the first year. The maximum Cr and Cr increase rate were significantly lower in the hANP group (p = 0.00665, p < 0.0001). There was no difference in mortality rate in the first year post-operatively, and fewer cardiac events and patients going on dialysis were found in the hANP group (p < 0.0001 and p = 0.0014, respectively). CONCLUSIONS In the post-operative acute stage, carperitide showed cardiorenal protective effects that prevented post-operative cardiac events and initiation of dialysis. Thus, perioperative infusion of low-dose carperitide may have a significant role in management of patients with renal dysfunction undergoing on-pump CABG. (Effectiveness of hANP for Cardiac Surgery in Patients With Moderate to Severe Preoperative Renal Dysfunction Without Dialysis [NU-HIT for CRF]; UMIN000001462).

Optimal treatment of type B acute aortic dissection: long-term medical follow-up results.

BACKGROUND The aim of this study is to assess the long-term outcome of medical treatment and determine recent surgical indications for type B acute aortic dissection. METHODS In the last 8 years, 79 patients were admitted to our hospital with type B acute aortic dissection. We medically treated patients at the time of onset, regardless of the aortic diameter and blood patency status in the false lumen. If the maximum diameter of dissected aorta exceeded 60 mm in any stage, early or elective surgery was performed. The mean follow-up duration was 41.2 months. We evaluated operation free rate and actuarial survival rate. RESULTS Thirteen patients underwent early or elective operations of the descending aorta. At the time of onset, the maximum aortic diameter of these patients was significantly larger than that of medically managed patients (55.8 +/- 4.4 mm vs 44.6 +/- 8.2 mm; p = 0.0004). Two patients underwent emergency axillo-femoral bypass for leg ischemia. Of the other 64 patients, who were medically managed, 2 patients had type A dissection develop during follow-up, 3 died during the initial hospital stay (1 from rupture, 1 from bronchial asthma, and 1 from gut ischemia), and 1 died of pneumonia 6 months after onset. Operation free rate was 98.6% at 1 month, 90.0% at 1 year, 78.7% at 3 years, and 69.5% at 8 years. Actuarial survival rate of medically managed patients was 98.4% at 1 month and 93.5% at 8 years. CONCLUSIONS Medical treatment of type B acute aortic dissection produced good results. Surgical intervention for type B dissection should be done when the maximum aortic diameter exceeds 60 mm.

Continuous Low-Dose Infusion of Human Atrial Natriuretic Peptide in Patients With Left Ventricular Dysfunction Undergoing Coronary Artery Bypass Grafting: The NU-HIT (Nihon University working group study of low-dose Human ANP Infusion Therapy during cardiac surgery) for Left Ventricular Dysfunction

OBJECTIVES Continuous low-dose infusion of human atrial natriuretic peptide (hANP) in patients undergoing cardiac surgery on cardiopulmonary bypass (CPB) inhibits the renin-angiotensin-aldosterone system and compensates for the adverse effects of CPB. BACKGROUND We examined the influence of hANP infusion on cardiac and renal function in patients with left ventricular dysfunction undergoing coronary artery bypass grafting (CABG). METHODS The subjects were 133 patients who underwent CABG and had a pre-operative ejection fraction < or =35%. They were randomized to receive 0.02 microg/kg/min of hANP from the initiation of CPB (hANP group) or placebo (saline) infusion. RESULTS Early post-operative mortality did not show a significant difference between the 2 groups, but perioperative complications were significantly less frequent in the hANP group (p = 0.015). Long-term all-cause mortality showed no difference, but the cardiac death-free rate at 5 or 8 years post-operatively was 98.5% in the hANP group and 85.5% in the placebo group (p = 0.0285). Post-operative ejection fraction was significantly larger and the post-operative brain natriuretic peptide level was significantly lower in the hANP group. Serum creatinine was significantly lower in the hANP group than the placebo group at 1 month, 6 months, and 1 year post-operatively, whereas the estimated glomerular filtration rate was significantly higher in the hANP group at these times. CONCLUSIONS In patients with left ventricular dysfunction undergoing CABG, hANP showed renal- and cardio-protective effects and reduced post-operative complications. It also improved the long-term prognosis. We suggest that hANP should be considered as part of perioperative management of patients with cardiac dysfunction undergoing cardiac surgery. (NU-HIT trial for LVD; UMIN000001652).

Study of the factors related to atrial fibrillation after coronary artery bypass grafting: a search for a marker to predict the occurrence of atrial fibrillation before surgical intervention.

OBJECTIVE Atrial fibrillation after cardiac surgery is a frequent complication. In this study we studied various factors in addition to trying to identify a marker that would predict the potential for atrial fibrillation before surgical intervention to prevent its occurrence. METHODS We targeted 234 cases in which isolated coronary artery bypass grafting had been performed. The items for study included age, EuroSCORE, and maximum values of creatine phosphokinase-MB, troponin I, and angiotensin II after surgical intervention and preoperative values of atrial natriuretic peptide, brain natriuretic peptide, and C-reactive protein. As fibrotic markers, we measured levels of the sialylated carbohydrate antigen KL-6 in the blood, hyaluronic acid, and pyridinoline cross-linked carboxyterminal telepeptide of type I collagen C. At the time of surgical intervention, a section of the right atrium was extracted, and atrial natriuretic peptide, the sialylated carbohydrate antigen KL-6, hyaluronic acid, and pyridinoline cross-linked telopeptide of type I collagen levels were measured. RESULTS Atrial fibrillation was observed in 73 (31.2%) cases, and preoperative factors that showed statistically significant differences in the occurrence of atrial fibrillation included age, EuroSCORE, and preoperative values of atrial natriuretic peptide, angiotensin II, the sialylated carbohydrate antigen KL-6, hyaluronic acid, and pyridinoline cross-linked telopeptide of type I collagen in the blood. As for intraoperative and postoperative factors, statistically significant differences were observed in the postoperative maximum of angiotensin II, atrial natriuretic peptide of the right atrium, the sialylated carbohydrate antigen KL-6, hyaluronic acid, and pyridinoline cross-linked telopeptide of type I collagen levels. CONCLUSION The fibrosis of tissue associated with age is believed to be closely related to the occurrence of atrial fibrillation after coronary artery bypass grafting. This study suggests that the preoperative values of atrial natriuretic peptide, angiotensin II, the sialylated carbohydrate antigen KL-6, hyaluronic acid, and pyridinoline cross-linked telopeptide of type I collagen in the blood are useful as a new index for the occurrence of atrial fibrillation after coronary artery bypass grafting.

Should emergency surgical intervention be performed for an octogenarian with type A acute aortic dissection

OBJECTIVE The number of octogenarians undergoing emergency surgery is increasing and may negate the impact of the beneficial advances. The aim of this study was to review octogenarians with type A acute aortic dissection and assess the prognosis. METHODS Fifty-eight patients with acute aortic dissection, whose average age was 83.2 years, were divided into 2 groups: Group I comprised 30 patients who underwent emergency surgery, and group II comprised 28 patients who were treated conservatively. We compared the 2 groups in terms of mortality and morbidity. RESULTS In group I, postoperative hospital mortality was 13.3% (4 patients). In group II, 17 patients (60.7%) died in the hospital. In group I, although emergency aortic replacement was successfully completed, 5 patients became bedridden after surgery and 2 patients died of pneumonia or stroke in the early stages of institutional care. Thirteen patients in group I died of malignancies, abdominal aortic rupture, traffic accident, heart failure, or late-stage senility in later phase. There was no difference in actuarial survivals at 5 years, which were 48.5% in group I and 35.4% in group II. CONCLUSION Emergency surgery for octogenarians with acute aortic dissection showed acceptable mortality. However, families had to take responsibility for patients who experienced unconsciousness, had dementia, or became bedridden. It is important to have consensus between the family and surgeons about emergency surgical treatment for octogenarians.

Less invasive quick replacement for octogenarians with type A acute aortic dissection

OBJECTIVE We assessed the efficacy of our newly modified technique, namely, less invasive quick replacement with rapid rewarming, for octogenarians undergoing emergency surgery for type A acute aortic dissection. METHODS Forty-two patients with acute aortic dissection, whose average age was 81.7 +/- 2.3 years, were divided into two groups: group I consisted of 25 patients undergoing surgery with deep hypothermic circulatory arrest and selective cerebral perfusion; group II consisted of 17 recent patients who underwent less invasive quick replacement. In the latter technique, during open distal anastomosis with a rectal temperature of 28 degrees C without any cerebral perfusion, circulating blood in the cardiopulmonary bypass circuit was warmed to 40 degrees C accompanied by warming of the patients body by a heating mat. As soon as the distal anastomosis was completed, rapid rewarming was initiated by 40 degrees C blood perfusion. RESULTS The durations of cerebral protection (group I, 75.8 minutes, vs group II, 18.8 minutes), cardiopulmonary bypass (I, 201.2, vs II, 84.4 minutes), and overall operation (I, 425.6, vs II, 148.6 minutes) were significantly shorter in group II. In group I, 5 patients had complications of cerebral damage and 5 required re-exploration for bleeding, 7 had pneumonia, 6 required hemodialysis for renal failure, and the hospital mortality rate was 24% (6 patients). On the other hand, no such complications or mortality were observed in group II (P < .0291). Postoperative hospital stay was significantly shorter for the patients in group II than in group I (13.2 days vs 33.7 days; P < .0001). CONCLUSION Less invasive quick replacement is safe and effective. It should be a standard surgical technique for octogenarians with type A acute aortic dissection.

Fifteen years of experience with ATS mechanical heart valve prostheses

BACKGROUND ATS Medical, Inc, developed a mechanical heart valve that has been in use since 1992. In this article, we present the results of 15 years of follow-up of patients who have undergone ATS heart valve replacement at our hospital. METHODS AND RESULTS We performed ATS heart valve replacements on 231 patients between September 1993 and March 2008. Our operative mortality rate for the study period was 2.2%. The survival for postoperative thromboembolic events was 0.29%/pt-y for aortic valve replacement, 0.48%/pt-y for mitral, 0.80%/pt-y for double valve replacement, and overall 0.44%/pt-y. The survival after bleeding events was 0.29%/pt-y for aortic valve replacement, 0.16%/pt-y for mitral, 0%/pt-y for double valve replacement, and overall 0.19%/pt-y. Patient-prosthesis mismatch, as determined by echocardiography, was found in 83.3% of patients at 19 mm, but other sizes showed good valve function. Prosthetic valve noise was undetectable in 92.8% of patients, and quality of life was excellent. CONCLUSIONS Few prosthetic valve-related complications were seen with ATS heart valve replacements in this study, and the follow-up results were favorable. The international normalized ratio was maintained in the range 1.6 to 2.0 in patients with aortic valve replacement in sinus rhythm. Not only bleeding events, seen at a rate of 0.19%/pt-y, but also thromboembolic events, at 0.44%/pt-y, were low when compared with conventional mechanical valves. Prosthetic valve noise is low, and this appears to be an excellent mechanical valve from the quality of life standpoint. The ATS valve has an excellent safety profile when compared with other mechanical valves.

Mechanical circulatory support for fulminant myocarditis

PurposeFulminant myocarditis is potentially fatal because it progresses rapidly into cardiogenic shock; thus, immediate and appropriate treatment is essential. Mechanical circulatory support (MCS) is an important part of treatment for fulminant myocarditis. We review our experience of treating fulminant myocarditis with MCS.MethodsWe used MCS with veno-arterial bypass (VAB) to treat seven patients with fulminant myocarditis. Five of these patients were younger than 18 years old. The mean time from arriving at our institution to the initiation of MCS was 15.9 ± 22.6 h. MCS was initiated within 18 h in six patients.ResultsThe mean assist time of MCS was 70.9 ± 35.0 h and six patients were weaned successfully (weaning rate: 85.7%). The remaining patient required support with VAB for 132 h, and a left ventricular assist device was applied. All seven patients were weaned off MCS and discharged.ConclusionsSince severe and rapid hemodynamic compromise is typical of fulminant myocarditis, an immediate decision must be made about whether to initiate MCS. We attribute the excellent results and favorable long-term prognosis of our patients to the early initiation of MCS.

Surgical Treatment of an Aortoesophageal Fistula Caused by Stent Implantation for Esophageal Stenosis: Report of a Case

An aortoesophageal fistula is uncommon, but almost always fatal. We report a case of an aortoesophageal fistula that developed after stent dilation for an esophageal stricture caused by benign esophagitis. As soon as esophageal hemorrhaging was identified by endoscopy, the patient was transferred to the operating theater; however, the uncontrollable and massive bleeding resulted in pulseless shock. The digestive surgeon put side-clamps on the descending aorta and esophagus and transferred the patient to our hospital. We identified an aortoesophageal fistula, 3.0 mm in diameter, in the descending aorta, and performed a graft replacement of the descending aorta and esophagectomy. It was immediately evident that the edge of the stent had been sticking into the aortic wall, which had caused the fistula. To our knowledge, this is the first report of successful surgical treatment of an aortoesophageal fistula caused by esophageal stent dilatation.