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Biomedical subjects

D M Nicoloff

Publications and source records attributed to D M Nicoloff.

At least 19 recordsLinked to original sources
PubMed2001

The initial United States experience with the ATS mechanical cardiac valve prosthesis.

From January 1, 1997 through June 30, 2000, 224 patients underwent valve replacement with the ATS Medical cardiac valve prosthesis under a USFDA-approved investigational device exemption study. Aortic valve replacement (AVR) was conducted in 152 patients (39 with coronary bypass) and mitral replacement (MVR) in 72 patients (18 with coronary bypass). Overall operative mortality was 1.8% (AVR = 2.8%, MVR = 0%), with only one valve-related death. In 372 patient-years of follow-up, there were an additional four patient deaths, two of which were valve related following a stroke. Valve-related complications included: thromboembolism (linearized rate = 3.8% per patient year), of which 3/11 had chronic deficits (0.8% per patient year); thrombosis (1 MVR = 0.8% per patient year); paravalvular leak (1 AVR = 0.4% per patient year); anticoagulant-related hemorrhage (1 AVR and 5 MVR = 1.6% per patient year) with no patient mortality; prosthetic valve endocarditis (1 MVR = 0.8% per patient year); and valve dysfunction (0%). Echocardiographic gradients were proportional to valve size and did not significantly change over the follow-up period. This study documented the ATS Medical prosthesis to be a valuable addition to the surgeon's armamentarium in the treatment of cardiac valvular disease.

Adult↗
PubMed2000

Does multivessel, off-pump coronary artery bypass reduce postoperative morbidity?

BACKGROUND: Off-pump coronary artery bypass (OPCAB) is an emerging procedure. It is assumed that elimination of cardiopulmonary bypass for coronary artery bypass grafting has the potential for reducing postoperative morbidity. This review evaluates the safety and impact of multivessel OPCABG as compared to CABG. METHODS: A retrospective review of 744 patients undergoing multivessel coronary artery bypass between January 1, 1997, and March 31, 1999, was done. The total population was divided into two groups: group A (n = 609 cardiopulmonary bypass) and group B (n = 135 OPCAB). This consecutive study cohort was elective status, full sternotomy with three or more distal anastomoses performed at a single institution. RESULTS: The mean risk adjusted predicted mortality was 2.3% in group A and 2.7% in group B (p = NS), with the mean number of distal anastomosis being greater in group A (3.8 vs 3.5/patient, p < 0.001). Major postoperative complications were similar but were not statistically significant between groups. Postoperative blood loss and use of blood transfusions were the only significant variables (p < 0.001). CONCLUSIONS: Multivessel OPCABG can be safely performed in selected patients. Elimination of cardiopulmonary bypass did not significantly reduce postoperative morbidity. Prospective randomized trials and long-term follow-up are needed to better define patient selection and the role of OPCABG.

Aged↗
PubMed1998

Clinical evaluation of the on-line Sensicath blood gas monitoring system.

BACKGROUND: Blood gas analysis is an integral part of the management of open heart surgery and post-surgical intensive care patients. This study was conducted to compare the results of on-line blood gas analysis using the new Sensicath (SC) optical sensor technology against standard blood gas assay. METHODS: Comparative blood gas analysis was performed on 45 postoperative cardiovascular surgical patients and 5 patients during cardiopulmonary bypass. Simultaneous samples were obtained. One sample was sent to the central hospital laboratory for measurement using a Radiometer ABL 500 blood gas analyzer and the second sample was drawn past the optical sensor. Comparisons between the two methods for pH, pO2 and pCO2 were analyzed using linear regression and the method of Bland and Altman for the intensive care unit samples (N = 451) while the T test was used to compare data points obtained during cardiopulmonary bypass (N = 57). Bias, accuracy and precision were also calculated. RESULTS: The regression lines (r2) for pH, pO2, and pCO2 and were 0.69, 0.94, and 0.68 with slopes of 1.000, 0.0957, and 1.052 respectively for postoperative surgical patients. During cardiopulmonary bypass, the T test did not show any significant difference between the Sensicath and the reference values for the arterial and venous pH, pO2 and pCO2. CONCLUSIONS: In summary, this study found the Sensicath to be an accurate, useful tool which permits immediate blood gas analysis without blood exposure and constitutes an advance in the field of intensive care monitoring.

Blood Gas Analysis↗
PubMed1997

Minimally invasive direct coronary artery bypass grafting: experimental and clinical experiences.

BACKGROUND: This communication briefly details the goals, indications, surgical approaches, and limitations of minimally invasive direct coronary artery bypass grafting (MIDCABG). The experimental experiences from various institutions are summarized. METHODS: The clinical experiences of 72 consecutive MIDCABG procedures performed at our institutions between June 5, 1995, and August 13, 1996, were analyzed. We have divided patients into two groups. Group A consists of healthy low-risk patients with single lesions of the left anterior descending coronary artery or the right coronary artery, or with both lesions of both arteries. Group B consists of high-risk patients who had major contraindications to conventional cardiopulmonary bypass procedures. There were 55 patients in group A and 17 patients in group B. Using The Society of Thoracic Surgeons preoperative predicted risk module, group A had a 1% predicted mortality versus 4% in group B. RESULTS: The 30-day mortality was 2% in group A and 6% in group B. The mean postoperative length of stay was 4 days for group A and 5 1/2 days for group B. Short-term follow-up of the survivors appears promising, and 81% of patients were angina free at the time of last follow-up. CONCLUSIONS: The MIDCABG techniques are still developing. The short-term results during the learning period appear to be quite good, but long-term results remain yet to be seen. The addition of new equipment to facilitate construction of the anastomosis will enhance application and results. The lessons learned from these approaches are already being applied to other areas of cardiac surgery including valve replacement and the repair of congenital heart defects.

Coronary Artery Bypass↗
PubMed1996

Mini-sternotomy for coronary artery bypass grafting.

This communication details the approach to the left anterior descending artery, right coronary artery, or both via a single limited incision of the chest. The mini-sternotomy incision is 10 to 12 cm long. The distal anastomosis can be accomplished, with a beating heart, through this small incision, with or without cardiopulmonary bypass.

Cardiopulmonary Bypass↗
PubMed1996

North American experience with the Perma-Flow prosthetic coronary graft.

BACKGROUND: The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives. METHODS: Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study. RESULTS: Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 +/- 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft. CONCLUSIONS: The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.

Aged↗
PubMed1996

Utilization of the St. Jude Medical prosthesis in the aortic position.

Intensive in vitro and in vivo studies led to the clinical introduction of the St. Jude Medical (SJM) prosthesis in October 1977. Because of excellent clinical characteristics, handling, and durability, as well as the low incidence of clinically adverse events, the SJM valve has become the most commonly used prosthetic heart valve. In 1,431 patients undergoing aortic valve replacement during a 15-year period, the incidence of clinically adverse events, including thromboembolism, thrombosis, paravalvar leak, reoperation and anticoagulant-related hemorrhage, have been less than 0.8% per patient-year in both adult and pediatric patients. There have been no structural failures. The SJM prosthesis is an excellent device for the treatment of diseases of the aortic valve.

Adolescent↗
PubMed1996

Anticoagulant related complications in elderly patients with St. Jude mechanical valve prostheses.

BACKGROUND AND AIMS OF THE STUDY: This communication reports the anticoagulant-related complications (ARH) in patients who received the St. Jude Medical mechanical prosthesis and were 70 years of age or older at the time of implantation. METHODS: Our institutional data file shows that during the 15-year period from 1977 to 1992, our group implanted the St. Jude Medical mechanical prosthesis in 610 patients with aortic valve disease (AVR) and 186 patients with mitral disease (MVR), who were 70 years or older, either with or without coronary artery bypass grafts. The operative mortality was 6.4% for AVR and 16% for MVR. The mean follow up for this elderly group was 4.9 years (2,996 patient-years) for AVR and 4.2 years (771 patient-years) for MVR. RESULTS: The incidence of late death was 30% for AVR and 33% for MVR. The freedom from TE was 91.6% +/- 1.8%, from valve thrombosis 98.8% +/- 0.7%, and from ARH 95.9% +/- 1.1%. The freedom from operative death, valve-related death, and all complications was 78.8% +/- 2.4%. The data from this study shows that both the aortic and the mitral valve replacement patients who were 70 years or older have an acceptable rate of bleeding complications. Reduction of the intensity of anticoagulation in our practice (INR of 1.8-2.5 for AVR and 2.5-3.2 for MVR) may play a role in this finding. The incidence of valve thrombosis and TE rates were also low in this study. CONCLUSIONS: With increasing life expectancy in the elderly, the use of the St. Jude Medical Mechanical prosthesis and low intensity anticoagulation could be reconsidered for a selected group of elderly patients.

Aged↗
PubMed1995

Long-term follow-up of the St. Jude Medical prosthesis in pediatric patients.

BACKGROUND: The St. Jude Medical prosthesis has become the most commonly used artificial heart valve, yet few data are available in the pediatric population. This study addresses results of the use of this prosthetic valve in pediatric patients over a 13-year time frame. METHODS: From January 1982 through June 1994, 73 patients (49 male) underwent 75 valve replacements using the St. Jude Medical prosthesis at Minneapolis Children's Medical Center. Follow-up was complete in 71 patients, with a mean follow-up of 39 +/- 32 months (mean +/- standard deviation; range, 4 to 142 months). RESULTS: Valves' positions were aortic in 36 patients, mitral or left atrioventricular valve in 34, tricuspid in 1, and double valve in 2. Patient age was 8 +/- 6 years, with a range of 1 week to 19 years. Sixteen patients were less than 24 months of age at valve replacement. Prior cardiac procedures had been performed in 82% of mitral patients, 58% of aortic patients, and all of the tricuspid and double-valve patients. Elective valve replacement was performed in 62 to 73 patients (85%). Seven patients (44%) less than 24 months of age had urgent valve replacement; 4 patients (7%) older than 24 months required urgent valve replacement. Overall early mortality was 8% (6 of 73); 36% (4 of 11) in the patients undergoing urgent valve replacement and 3% (2 of 62) in the elective group. All but one of the deaths were due to cardiac dysfunction. There were four late deaths, from 4 to 125 months postoperative, primarily caused by congestive heart failure or pulmonary vascular disease. Cumulative freedom from valve-related events was 93%, 85%, and 77% at 1, 5, and 10 years, respectively. Valve-related complications included thromboembolism (4), bleeding (5), perivalvar leak requiring reoperation (2), transient ischemic attack (1), and endocarditis (1). There have been no permanent strokes or mechanical malfunction. The majority of patients are currently managed with warfarin. Five surviving patients whose initial valve replacement was at age 24 months or younger have undergone repeat valve replacement (42%). Ninety-five percent of patients enjoy good health at follow-up. CONCLUSIONS: The St. Jude Medical prosthesis offers correction of valvular disease with low morbidity and mortality, and excellent functional result.

Adolescent↗
PubMed1995

Modification of the elephant trunk procedure for treatment of acute aortic dissection.

The distal anastomosis constructed during repair of an aortic dissection is prone to bleeding, reentry, and neodissection. To protect the hemostasis, a modification of Borst's elephant trunk procedure has been devised. This "mini-trunk" protects the anastomosis with an internal buttress using the crease of an infolded graft and with a short flap of graft everted into the distal lumen preventing access of the blood stream to this newly constructed suture line.

Acute Disease↗
PubMed1994

Operative considerations in implantation of the Perma-Flow graft.

The Perma-Flow coronary bypass graft (Possis Medical, Inc, Minneapolis, MN) currently is undergoing expanded clinical trial. From November 1992 through June 1994 we have used this artificial conduit in 8 patients without autologous alternatives. These cases allowed the establishment of a technical basis for successful implantation of this graft. All studied coronary anastomoses are patent.

Aorta↗
PubMed1993

First clinical use of the Possis synthetic coronary graft.

The Possis polytetrafluoroethylene Permaflow coronary graft incorporates a Venturi resistor within the graft. Insertion is constructed by creating an anastomosis to the superior vena cava with subsequent anastomoses in sequence to coronary arteries requiring grafting. Finally, the graft is sewn to the aorta. The Venturi resistor controls flow through the aortocaval fistula, maintaining systemic pressure proximal, permitting systolic and diastolic flow to the grafted coronary arteries while maintaining constant flow through the graft. Animal studies demonstrated long-term patency. This graft was implanted in a patient with unstable angina pectoris and inadequate native conduit. Catheterization 6 weeks postoperative revealed patency of all anastomoses.

Aged↗
PubMed1989

Ten years' experience with the St. Jude Medical valve prosthesis.

Records of 1,298 consecutive patients who had received the St. Jude Medical prosthesis were reviewed (713 male and 585 female patients; mean age, 61.79 +/- 13.4 years). Early mortality was 5.7% (74 patients). Ninety-three percent complete follow-up was accomplished for the 1,224 patients who left the hospital (4,306.50 patient-years). One hundred ninety-two of these patients died, a late mortality of 16.9%. Sixty-four patients experienced thromboembolic episodes (17 major and 35 permanent). Twenty-four patients had anticoagulant-related bleeding, 4 had valve thrombosis, 7 had prosthetic valve endocarditis, 9 had paravalvular leak, and 10 underwent reoperation. There was no structural valve failure in this series. Twenty-two of the 118 patients who had valve-related complications died; another 15 patients died of sudden and unknown causes. Therefore, the total number of valve-related deaths was 37. Of those patients who survived, New York Heart Association functional class improved significantly (98% in classes II and III preoperatively and 96% in classes I and II postoperatively). Linearized rates for thromboembolism, valve thrombosis, and anticoagulant-related bleeding were 1.49% +/- 0.19%, 0.09% +/- 0.05%, and 0.56% +/- 0.11%/100 patient-years, respectively. The actuarial estimate of incidence free from all complications, operative death, and valve-related death was 66.9% +/- 8.2% at the end of 9 years. In spite of old age and advanced heart disease, the patients who received the St. Jude Medical prosthesis had very good results over a 10-year period.

Actuarial Analysis↗
PubMed1989

Ten-year follow-up study of patients who had double valve replacement with the St. Jude Medical prosthesis.

Records of 100 consecutive patients who had received double valve replacement were reviewed (41 men, 59 women, mean age, 60.86 +/- 13.0 years). The early death rate was 6% (six patients). A completed follow-up rate of 93% was accomplished in these 94 patients who left the hospital (mean, 309.8 patient-years). Twenty-three of these patients died. The late death rate was 26.4%. Four patients experienced thromboembolic episodes (one transient and three permanent; all were minor). One patient had a paravalvular leak (mitral), and another had thrombosis of the tricuspid valve. There was no clinical evidence of hemolysis, infective endocarditis, or structural failure or anticoagulant-related bleeding. One of those 23 patients who died was the patient who had thrombosis of the tricuspid valve. Another three patients died of sudden and unknown causes, 15 of cardiac-related problems and four of noncardiac problems. Of those patients who survived, New York Heart Association functional class improved significantly (from 66% class III before to 85% class I after). Linearized rates for thromboembolism and thrombosis were 1.29 +/- 0.65 and 0.32 +/- 0.32 per 100 patient-years, respectively. The actuarial estimates of incidence free of all complications and valve-related deaths were 77.9% +/- 10.6%. Despite the advanced heart disease involving two native valves, the patients who had double valve replacement with the St. Jude Medical prosthesis had very good results over a 10-year period.

Actuarial Analysis↗
PubMed1989

Mechanical circulatory support as a bridge to transplantation.

From December 1985 through April 1988, 11 patients (three female and eight males), 33.1 +/- 3.9 (+/- SEM) years of age (range, 15 to 50 years), underwent heart transplantation preceded by the use of mechanical circulatory support. The causes of cardiac failure were ischemic (four), viral cardiomyopathy (three), idiopathic cardiomyopathy (two), congenital heart disease (one), and valvular heart disease (one). All patients were preterminal. Mechanical circulatory support consisted of intra-aortic balloon pump (eight), the total artificial heart (seven), biventricular assist (three), and left ventricular assist (two). Seven patients had more than one form of support. The duration of mechanical circulatory support was 12.2 +/- 4.1 days (range, 1 to 44 days). Once listed for transplantation, patients waited for 8.1 +/- 2.4 days for a donor. Seven patients received OKT3 monoclonal antibody as prophylaxis, in addition to triple-drug immunosuppression. There were four rejection episodes and 12 serious infections. In addition, eight patients suffered a major posttransplant complication of a distant organ system: central nervous system (three), renal (two), and respiratory (three). Post transplant hospitalization was 48 +/- 22 days (range, 15 to 248 days). Two patients (18%) died after transplant, one of severe acute rejection (29 days) and one of multisystem failure (248 days). All patients surviving transplant hospitalization are alive 6 to 34 months after the transplant procedure. Eight patients are in functional class I and 1 patient class II. This patient attends school full-time but has a premechanical support system neurologic defect. In follow-up of 163 patient-months except for yearly catheterization, these nine patients required only 5 hospital days. Although the use of the mechanical circulatory support as a bridge to transplantation can result in a prolonged, complicated hospitalization after transplant, the long-term results are gratifying.

Adolescent↗
PubMed1987

St. Jude Medical prosthesis: valve-related deaths and complications.

Despite the hemodynamic improvement in cardiac valve prostheses, valve-related deaths and complications have remained a substantial source of morbidity and mortality. This follow-up study was carried out in April, 1986, in a group of 816 patients who received 876 St. Jude Medical prostheses between October, 1977, and October, 1984. One hundred fifty-five patients (37%) of the 422 having aortic valve replacement (AVR) and 88 (29%) of the 300 having mitral valve replacement (MVR) had concomitant coronary artery bypass grafting, and 94 patients (12%) had miscellaneous procedures performed in addition to valve replacement. Sixty-three patients died within the operative period, an operative mortality of 7.7%. Follow-up was complete for 98% of the patients; the mean follow-up was 42 months. At that time, 87 more patients had died, a late mortality of 11.9%. There were 13 valve-related deaths (4 in the AVR group, 7 in the MVR group, and 2 in the miscellaneous group); the causes of death were thromboembolism (7), anticoagulant-related hemorrhage (2), valve thrombosis (2), prosthetic valve endocarditis (1), and perivalvular leak (1). There were 37 thromboembolic episodes (1.78/100 patient-years) and 67 anticoagulant-related hemorrhages (3.22/100 patient-years), 46% of which necessitated transfusion. The incidence of valve thrombosis was 0.6% (4 patients). Perivalvular leak and prosthetic valve endocarditis occurred in 7 patients (1.0%) and 5 patients (0.7%), respectively. Reoperation was carried out in 6 patients (0.8%), but only for perivalvular leak. There were no deaths, no complications, and no clinical evidence of malfunction of the prosthetic valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗