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Biomedical subjects

K V Arom

Publications and source records attributed to K V Arom.

At least 19 recordsLinked to original sources

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

Evaluation of 7,000+ patients with two different routes of cardioplegia.

BACKGROUND: This study examined the efficacy and safety of retrograde cardioplegia in comparison with an antegrade/retrograde approach. METHODS: Between January 1, 1991, and December 31, 1995, 7,032 coronary artery bypass procedures, alone or in combination with valve replacement/repair, were performed using either retrograde cardioplegia (R) or an antegrade/retrograde (AR) approach. There were 4,224 patients in the R group and 2,808 in the AR group. These included elective, urgent, emergent/salvage, first operative, and redo cases. RESULTS: All preoperative, intraoperative, and postoperative variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to compare the two groups using univariate analysis. The pump time was longer in the AR group, with fewer grafts per patient. The R group had higher predicted risk (3.2% versus 3.0%; p = 0.04), more postoperative atrial fibrillation (34% versus 31%; p = 0.006), and longer postoperative length of stay (8.8 versus 8.0 days; p < 0.001). Using The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group model, a subgroup of 221 coronary artery bypass grafting patients in the retrograde (s-R) and 132 coronary artery bypass grafting patients in the antegrade/retrograde (s-AR) group fell into a greater incidence of predicted mortality group (> or = 10%). The s-R subgroup had more patients in New York Heart Association functional class IV. Univariate analysis revealed higher postoperative atrial fibrillation (51% versus 41%; p = 0.05) and longer postoperative length of stay (12.8 versus 10.8 days; p = 0.03) in the s-R subgroup versus the s-AR subgroup. CONCLUSIONS: The results appear to favor neither approach. Preoperatively, both retrograde groups (R and s-R) had higher preoperative predicted risk, but operative mortality or complications were not significantly increased when compared with the AR and s-AR groups. Retrograde cardioplegia alone was shown to be effective in the R and s-R groups, but atrial fibrillation developed in more patients, which could have contributed to longer length of stay in these groups. Antegrade/retrograde cardioplegia offers good immediate outcome but the delivery method can be cumbersome and confusing during the adjustments of flow clamps for antegrade/retrograde delivery and may contribute to prolonged pump times. From this retrospective, nonrandomized review, it appears that retrograde cardioplegia alone provides as good myocardial protection and safety as an antegrade/retrograde approach in either the low-risk or high-risk patient.

Atrial Fibrillation

Establishing and using a local/regional cardiac surgery database.

BACKGROUND: In 1993, the Minnesota Society of Thoracic Surgeons and the Minnesota Cardiac Surgery Database were organized in response to a third-party payer demand for data about practice protocols and patient outcomes. It has matured to an active organization of 46 cardiothoracic surgeons, 14 institutions, and more than 7,000 patients who have undergone coronary artery bypass grafting. METHODS: Data are validated for completeness and accuracy through a statewide auditing process. They are coded by hospital, analyzed using the standard Society of Thoracic Surgeons National Cardiac Surgery Database format and definitions, and reviewed quarterly in a continuous quality improvement process. RESULTS: Through data review and exchange site visits, variations in practice protocols and outcomes have been identified. For example, our statewide data review and continuous quality improvement process identified prolonged ventilation (more than 24 hours) as one variation. Multidisciplinary teams were defined, and statewide exchange site visits led by cardiovascular surgeons were implemented. An example of the improvement in the accuracy and completeness of the data used to study procedure outcomes is represented by the improved reporting of ejection fraction values that has resulted from this process. CONCLUSIONS: Using the standardized Society of Thoracic Surgeons National Cardiac Surgery Database and the Minnesota Society of Thoracic Surgeons organizational structure to establish a high-quality database will allow for statewide peer review, exchange of practice guidelines, and promotion of standardization, which eventually can improve outcomes and reduce costs. This organization or model can be replicated at any local, state, or regional level. Thoracic surgeons faced with similar challenges for public disclosure of surgical results can learn much from the successful development of the Minnesota Cardiac Surgery Database.

Clinical Protocols

Patient characteristics, safety, and benefits of same-day admission for coronary artery bypass grafting.

BACKGROUND: The move toward outpatient and same-day surgery has been phenomenal in the past several years. Efforts in this area have focused on limiting inpatient hospitalization, reducing ancillary services, and decreasing length of stay. METHODS: Two hundred seventy-six DRG 107 patients who were operated on at our institutions in 1994 and registered in The Society of Thoracic Surgeons National Cardiac Surgery Database were reviewed. There were 185 patients randomly admitted to the hospital on the day of operation and 91 patients admitted 1.78 +/- 1.94 days before. These patients were analyzed according to The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group and expected operative mortality modules. Univariate analysis of all risk variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to identify the difference between 176 elective procedure patients in the same-day admission group and 67 elective procedure patients in the non-same-day admission group. RESULTS: The same-day admission group had lower expected operative mortality (1.3% versus 2.9%), fewer female patients (17% versus 29%), younger age (62 versus 67 years), and fewer patients in the higher predicted risk group. Univariate analysis showed only age and ejection fraction variables were significantly different between the two elective groups. Comorbidities predictive of elective non-same-day admission revealed that age and New York Heart Association class IV were significant predictors. The length of stay was shorter and the total charges were less in the same-day admission group. CONCLUSIONS: There was no increase in preoperative, intraoperative, or postoperative complications in the same-day admission patients. Same-day admission was safe and cost-effective and could be carried out as a routine admission for several selected groups of patients.

Aged

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

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

Revascularization using angioplasty and minimally invasive techniques documented by thermal imaging.

Minimally invasive direct coronary artery bypass grafting offers mortality and morbidity advantages to selected patients. To broaden indications for such, an appropriate and combined disciplinary approach using angioplasty and minimally invasive direct coronary artery bypass grafting is described in a patient requiring reoperative grafting. Documentation of patency of new left internal mammary artery-to-left anterior descending artery anastomoses performed without the use of cardiopulmonary bypass was obtained intraoperatively using a Thermal Imaging Camera.

Aged

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

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

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

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

Warm heart surgery: a prospective comparison between normothermic and tepid temperature.

Due to concerns about complications from normothermic core temperature during cardiopulmonary bypass, we initiated a prospective randomized study of 200 consecutive patients. In one group (group A), both the heart and the body temperature were kept at 37 degree C. In the second group (group B), both the body and myocardial temperature were allowed to drift down to 34 degree C. There were no differences between these two groups in age, sex, preoperative numbers of elective, urgent, emergent, redo patients, or coronary artery bypass (CAB), valve, CAB/valve procedures. Their preoperative neurological, pulmonary, renal, and vascular disease status were similar. Preoperative EF was 53% in group A (100 patients) and 52.5% in group B (100 patients). Group A required more volume (p = 0.001) and had less urine output (p = 0.03) during and post bypass. Group A required more phenylephrine hydrochloride (p = 0.05) and had more difficulty managing blood pressure. Strokes and renal failure necessitating dialysis occurred more often in group A but without statistical significance. More difficulties occurred in the normothermic (37 degrees C) group and cardioprotective effects of warm heart surgery may remain intact at 34 degrees C. Mild "drifted/tepid" hypothermic heart surgery could be a better and safer procedure.

Body Temperature

Thrombolytic therapy of left-sided prosthetic valve thrombosis.

Thrombosis of left-sided prosthetic valves is an uncommon yet potentially serious complication. Thrombolytic therapy has been proposed as an alternative to surgical methods in treating this condition. We sought to determine from a review of the literature what outcomes may be expected subsequent to thrombolytic administration and what groups may be at risk or benefit from this approach. We searched for studies including two or more patients treated with thrombolytic agents. Ten studies were reviewed. We describe and include two patients with valve thrombosis treated at our institution. A total of 182 episodes of prosthetic valve thrombosis in 162 patients were examined. Clinical success was achieved in 72.0% of cases and there was a mortality risk of 9.9%. Clinical success from thrombolysis was significantly related to the degree of heart failure at presentation and aortic valve position. Clinical success was not related to the duration of symptoms, time from valve replacement to obstruction, or valve type. Rethrombosis of successfully treated valve occurred subsequently in 19.5% of cases. Repeated thrombolytic administration in these patients was associated with similar rates of success as those treated for their initial episode of prosthetic valve thrombosis. Candidates for thrombolytic therapy include patients with obstructive valve thrombosis with or without congestive heart failure who are hemodynamically stable. Duration of time since valve replacement or symptom onset does not limit successful outcome. Close observation and aggressive maintenance of anticoagulation after therapy is suggested.

Aged

Cost-effectiveness and predictors of early extubation.

BACKGROUND: This study examined predictors and cost-effectiveness of early extubation after coronary artery bypass grafting. METHODS: Six hundred forty-five patients admitted to intensive care units after coronary artery bypass grafting at our institutions in 1993 were reviewed. There were 455 male and 190 female patients, which included all patients in DRG 106 and DRG 107. The patients were categorized into three groups: group A (269 patients) were extubated in less than 12 hours (7.55 +/- 2.5 hours), group B (291 patients) were extubated between 12 and 24 hours (16.85 +/- 3.3 hours), and group C (376 patients) were extubated any time after 12 hours. RESULTS: The reintubation rate for the entire group was less than 1%. Univariate preoperative analyses revealed small differences between groups A and B: only 6 of 25 variables were found to reach statistical significance. Stepwise logistic regression analyses were carried out in 269 patients of group A and 376 patients of group C. Older patients (log of age, p = 0.0001), female sex (p = 0.0129; odds ratio = 1.634), use of preoperative diuretics (p = 0.0010; odds ratio = 1.965) and unstable angina (p = 0.0301; odds ratio = 1.544) were noted to be clinical factors associated with late extubation (> or = 12 hours). Early extubation was accomplished in 42%; however, further analysis revealed that many patients who were intubated overnight should have been extubated sooner. CONCLUSIONS: Early extubation shortened the postoperative length of stay, resulting in reduction of cost and resource utilization. The average hospital charge per patient was approximately $6,000 less in the early extubation group.

Aged

Decreased postoperative drainage with addition of epsilon-aminocaproic acid before cardiopulmonary bypass.

Desmopressin (DDAVP, 0.3 microgram/kg) has been used routinely after cardiopulmonary bypass, particularly in patients having antiplatelet therapy. Recently epsilon-aminocaproic acid (single dose of 5 g) given before cardiopulmonary bypass has been added to the protocol. One hundred consecutive patients taking desmopressin and epsilon-aminocaproic acid (group A) and another 100 taking desmopressin alone (group B) were analyzed. There was no difference among these two groups in patient age, sex, preoperative history of bleeding and drug consumption, or number of patients for elective, urgent, emergent, redo, and reoperation for bleeding. Results of routine preoperative coagulation studies were within normal limits in both groups. Preoperative hemoglobin level was 13.5 g/dL in group A and 13.8 g/dL in group B (p = 0.12). Estimated blood loss in the operating room was 513 mL for group A and 587 mL for group B (p = 0.07). The total chest drainage at the end of 24 hours was 492 mL in group A and 746 mL in group B (p = 0.0001). Amicar given before cardiopulmonary bypass does not lessen operating room blood loss, but significantly decreases postoperative chest drainage. Group B patients received more fresh frozen plasma (60 U versus 4 U), more platelets (130 U versus 16 U), and more cryoprecipitate (118 U versus 10 U) than group A patients. Adding epsilon-aminocaproic acid could save $206.18 in blood product use per patient, compared with the expense of $24.12 per patient for E-aminocaproic acid administration.

Aminocaproic Acid

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