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Biomedical subjects

A Koshal

Publications and source records attributed to A Koshal.

At least 19 recordsLinked to original sources
PubMed2002

Troponin T and I are not reliable markers of cardiac transplant rejection.

OBJECTIVE: Heart transplant recipients undergo a number of invasive endomyocardial biopsies to screen for rejection. Serum assays of troponin T and/or I may provide a less invasive alternative. The purpose of this study was to evaluate troponin T and I as markers of cardiac transplant rejection. METHODS: We conducted a prospective analysis comparing troponin T and I levels to biopsy results in heart transplant recipients. Plasma was assayed for troponin T and I preoperatively, on the first 3 postoperative days, and with each subsequent biopsy. RESULTS: Twenty-nine patients entered the study. A total of 173 biopsies were performed at a mean follow-up of 129+/-9 days (range: 12-564 days). There were two rejection episodes (> or = grade 3), one in each of two patients. There were no significant relationships between troponin T or I and biopsy-proven rejection (> or = grade 3; P=0.59 and 0.54, respectively). There were also no correlations between troponin T or I levels and biopsy grade (P=0.40 and 0.92, respectively). Troponin T and I levels peaked on postoperative day 1 and fell to baseline over long-term follow-up with no peak in serum markers associated with rejection episodes. Donor ischemic time was significantly correlated to troponin T on postoperative days 1-3 (r=0.58, P=0.005; r=0.61, P=0.004; and r=0.61, P=0.003, respectively). CONCLUSIONS: Troponin T and I are not useful indicators of cardiac rejection, but do correlate with donor heart ischemic injury.

Biomarkers↗
PubMed2001

Long-term survival in 11,661 patients with multivessel coronary artery disease in the era of stenting: a report from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Investigators.

BACKGROUND: Studies of survival of patients with multivessel coronary artery disease (MVD) in the prestent era suggested that outcomes after coronary artery bypass surgery (CABG) are similar to those after percutaneous coronary intervention (PCI) in subsets of coronary severity. The purpose of this study of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) was to examine the association between treatment and survival up to 5 years in patients with MVD enrolled from 1995 through 1998. METHODS AND RESULTS: Data on patient characteristics were obtained at the time of the initial coronary angiography. Survival was determined through data linkage to the provincial Bureau of Vital Statistics. Risk-adjusted hazard ratios were calculated to compare different treatments. In the 11,661 patients with MVD, CABG was the initial therapy in 3782, PCI in 3540, and medical therapy in 4339. Cumulative 5-year survival was 91.4% with CABG, 91.9% with PCI, and 82.9% with medical therapy (P <.001). Hazard ratios were CABG: medical 0.53 (95% confidence interval [CI] 0.46-0.71), PCI: medical 0.65 (95% CI 0.56-0.74), and CABG: PCI 0.81 (95% CI 0.68-0.96). Analysis across coronary severity groups revealed a benefit of CABG compared with PCI only in the group with severe left main CAD: 0.30 (95% CI 0.17-0.54). CONCLUSIONS: In a multicenter clinical setting, MVD patients treated with revascularization have significantly higher 5-year survival rate than do those treated medically. Risk-adjusted comparison reveals PCI treatment to be associated with long-term survival similar to treatment with CABG in all coronary severity subgroups except the group with severe left main coronary artery disease. Patient selection factors are likely to be contributing to these findings.

Aged↗
PubMed2001

Extended donor ischemic times and recipient outcome after orthotopic cardiac transplantation.

BACKGROUND: The effect of extended donor ischemic times on mortality following heart transplantation is a matter of considerable debate. PATIENTS AND METHODS: A retrospective study of the 261 consecutive heart transplantations performed at the centre (University of Alberta, Edmonton, Alberta) between July 1985 and June 1999 was conducted. Patients were divided into the following two groups based on donor ischemic time: 4 h or less and longer than 4 h. Donor and recipient factors were analyzed for their effects on 30-day and 90-day survival. RESULTS: Thirty-day mortality was not significantly greater with prolonged donor ischemic times (13%) than with shorter ischemic times (7%, P=0.14). There was also no significant increase in 90-day mortality with longer ischemic times (16%) than with shorter ischemic times (10%, P=0.27). Actuarial survival (10 years) was similar between the groups (P=0.33). Predictors of 30-day and 90-day mortality were cardiopulmonary bypass time (P<0.001 and P<0.001, respectively) and lower donor weight (P=0.008 and P=0.02, respectively). CONCLUSIONS: Longer donor ischemic times were not significantly related to decreased 30-day, 90-day or 10-year actuarial survival.

Actuarial Analysis↗
PubMed1999

Reduction of leg wound infections following coronary artery bypass surgery.

OBJECTIVE: To reduce the rate of infection at the saphenous vein harvest site after coronary artery bypass surgery, to identify predictors of infection and to determine the best method for leg wound closure. DESIGN: A randomized clinical trial was undertaken to determine the best technique for reducing the postoperative leg wound infection rate. Patients were allocated to one of four leg wound closure methods: staples, close immediately; staples, close after protamine administration; subcuticular sutures, close immediately; and subcuticular sutures, close after protamine. Risk factors evaluated were age, sex, diabetes, obesity, peripheral vascular disease, reoperation, time in surgery, wound length, wound depth, time that the wound was open, wound quality and harvest site. SETTING: The Walter C Mackenzie Health Sciences Centre, University of Alberta, Edmonton, Alberta. PATIENTS: All consenting patients undergoing elective coronary artery bypass surgery involving saphenous vein harvesting were considered for the study. Exclusion criteria were insertion of a drain, insertion of an intra-aortic balloon pump in the index limb and inability to complete follow-up at the authors' centre. Eighty patients were initially enrolled, with 77 completing the study. INTERVENTIONS: Patients underwent standard saphenous vein harvesting followed by wound closure as indicated by the study group. MAIN RESULTS: The major infection rate was reduced from 13% to 3% (P = 0.02). Each closure method was equally effective, and wound depth was the only factor related to infection. CONCLUSIONS: Leg wound infections continue to be a major source of morbidity after coronary bypass surgery.

Aged↗
PubMed1999

Mechanical circulatory support as a bridge to cardiac transplantation: toward the 21st century.

Mechanical circulatory support is used to sustain the lives of patients awaiting cardiac transplantation who would otherwise die before a donor organ became available. Currently available ventricular assist devices used for mechanical circulatory support, risk factors and complications associated with use of these devices, and selection of candidates for treatment with mechanical support as a bridge to cardiac transplantation are reviewed. The importance of early insertion of the devices before end-organ dysfunction occurs is examined.

Forecasting↗
PubMed1998

Impact of managed waiting for coronary artery bypass graft surgery on patients' perceived quality of life.

BACKGROUND: Current demand for CABG surgery remains high, often exceeds available resources, and has led to the development of managed waiting lists. This study was designed to determine how being placed on a managed waiting list for > 6 weeks for CABG surgery affected patients' perceived quality of life in a Canadian center. METHODS AND RESULTS: Telephone interviews were carried out in the setting of a large urban hospital in northern Alberta. All participants were identified from 3 waiting lists of adult patients waiting for open heart surgery. A master list of patient statements was compiled to formulate the 47-item Waiting List Impact Questionnaire (WLIQ). A total of 102 patients completed the WLIQ by telephone interview. Patients (87.5%) indicated that their quality of life had deteriorated since being placed on the waiting list. None of the patients perceived an improvement in their quality of life. Frequency data for the WLIQ provided a broad, multidimensional perspective of the experience of waiting for CABG surgery and its impact on perceived quality of life. Negative impact was found in each of 5 main themes: employment and income, physical stress, social support, frustration, and quality of life. CONCLUSIONS: This study indicates that patients perceived a negative impact on their quality of life after being placed on a managed waiting list for CABG surgery. In the allocation of healthcare resources, attention should be paid to the impact of waiting on patients' physical well-being as well as on quality of life.

Adult↗
PubMed1998

Cardioprotection by activation of NO/cGMP pathway after cardioplegic arrest and 8-hour storage.

BACKGROUND: We determined whether activation of the nitric oxide/cyclic guanosine monophosphate pathway by sodium nitroprusside (SNP) protects hearts subjected to cardioplegic arrest and prolonged hypothermic storage. METHODS: Isolated rat hearts arrested with St. Thomas' II cardioplegia and stored at 3 degrees +/- 1 degree C for 8 hours were reperfused at 37 degrees C in Langendorff (10 minutes) and working (60 minutes) modes. RESULTS: During reperfusion, left ventricular work was depressed in stored hearts relative to fresh hearts. When present during arrest, storage, and both reperfusion phases, SNP (200 mumol/L) improved work to values close to those in fresh hearts. When added only during the 10-minute period of Langendorff reperfusion, SNP also improved the subsequent recovery of work. This effect was antagonized by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Poststorage coronary perfusion was not increased by SNP. CONCLUSIONS: The ability of SNP to enhance recovery independent of changes in coronary perfusion and in an ODQ-sensitive manner suggests that SNP-induced protection is due to activation of the myocardial nitric oxide/cyclic guanisine monophosphate pathway. These results suggest that supplementing cardioplegic solutions with SNP, administering SNP during early reperfusion, or both may offer additional means to improve donor heart preservation.

Animals↗
PubMed1997

Tricuspid endocarditis following a Papanicolaou smear: case report.

Infective endocarditis is an uncommon complication of obstetrical and gynecological practice and has not been reported in the literature to be associated with Papanicolaou smears. The authors report a nonintravenous drug user who developed group B streptococcal endocarditis of the tricuspid valve following a routine Papanicolaou smear. She required surgical excision of the valve and replacement after failed antibiotic therapy.

Adult↗
PubMed1995

Magnesium sulfate prophylaxis after cardiac operations.

One hundred patients undergoing elective cardiac operations were randomized into placebo (n = 54) and magnesium (n = 46) groups. The magnesium group received six doses of 2.4 g (19.2 mEq) magnesium sulfate intravenously in the first 24 hours after the cardiac operation. The magnesium group had higher serum magnesium concentrations postoperatively (1.09 +/- 0.20 versus 0.75 +/- 0.13 mmol/L; p < 0.0001), postoperative day 1 (1.49 +/- 0.34 versus 0.70 +/- 0.12 mmol/L; p < 0.0001) and postoperative day 2 (0.96 +/- 0.19 versus 0.76 +/- 0.07 mmol/L; p < 0.0001). Patients in the magnesium group had a lower incidence of ventricular tachyarrythmias (VTs) (17.3% versus 51.9%; p = 0.0006), less need for treatment (6.5% versus 20.3%; p < 0.0001), fewer VT episodes/patient (0.3 +/- 0.8 versus 1.39 +/- 1.9; p < 0.0001), and a reduction in the severity of VTs as measured by the modified Lown grade (p = 0.0002). No differences were demonstrated with respect to supraventricular tachyarrythmias. The magnesium group had reduced absolute creatine kinase-MB levels (5.3 +/- 4.2 versus 28.4 +/- 28 IU/L; p = 0.001) as well as creatine kinase-MB fraction (0.01 +/- 0.02 versus 0.05 +/- 0.04; p = 0.001) on postoperative day 1. Serum magnesium concentrations were lower during VTs than during periods of sinus rhythm (0.75 +/- 0.75 versus 1.02 +/- 0.35 mmol/L; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Efficacy of rapamycin, RS-61443 and cyclophosphamide in the prolongation of survival of discordant pig to rabbit cardiac xenografts.

OBJECTIVE: To evaluate the efficacy of two new immunosuppressive drugs, RS-61443 and rapamycin, alone and in combination with cyclophosphamide in the prolongation of heterotopic cardiac xenograft survival in a discordant neonatal pig to rabbit model. DESIGN: Animals were randomly assigned to receive rapamycin intravenously (1.0 mg/kg/day) or RS-61443 subcutaneously (160 mg/kg/day) commencing five days before surgery until rejection occurred. Cyclophosphamide, 20 mg/kg/day, was administered from one day prior to surgery. Combination of the above drugs (rapamycin 1.0 mg/kg/day and RS-61443 80 mg/kg/day) with and without treatment with cyclophosphamide was also evaluated. Trough blood concentrations of rapamycin and mycophenolic acid as well as rabbit antiporcine endothelial cell antibodies (immunoglobulin [Ig]M) were measured every second day from the commencement of drug therapy. RESULTS: The mean +/- SD survival time in control animals was 7.98 +/- 13.85 h (n = 11), with the majority of animals (n = 6) rejecting their grafts in less than 1 h. Rapamycin (11.5 +/- 9.5 h), RS-61443 (9.8 +/- 6.1 h), cyclophosphamide (17.9 +/- 16 h) alone, or the three drugs in combination (16.6 +/- 9.1 h) resulted in a trend to increase graft survival, which did not reach significance. In contrast, rapamycin and RS-61443 in combination (24.3 +/- 11.9 h) significantly (P < 0.05) prolonged graft survival. No significant (P > 0.05) decrease in rabbit antiporcine endothelial cell IgM concentrations was observed in all drug-treated groups; however, considerable variation was noted within each group. No relationship was found between trough concentrations of rapamycin and mycophenolic acid and xenograft survival or with a decrease in antibody concentrations. CONCLUSION: The data suggest that treatment modalities, in addition to the above drugs, is required for prolonged survival in cardiac xenografts in the discordant animal model used here.

Animals↗
PubMed1994

Cost reduction in cardiac surgery.

OBJECTIVE: To reduce surgical waiting lists at the University of Alberta Hospitals. A cost reduction program was initiated, allowing more cases to be performed on the same budget. Reducing the cost of delivering health care services has become necessary as demands upon the system increase. METHODS: Data were retrospectively gathered on patients having open heart surgery at the University of Alberta Hospitals between March 1, 1991 and February 29, 1992. Group 1 were patients operated on before the start of the cost reduction program (September 1, 1991) and group 2 were those operated on after. Student's t test and logistic regression were use to compare population characteristics and to correlate dependent variables. RESULTS: Demographic features and severity indices were not different. Operating time decreased from 4.5 +/- 1.5 to 4 +/- 1 h, P < 0.002. Preoperative, intensive care unit (ICU) and postoperative ward length of stay were reduced (P < 0.002). Total length of stay went from 19.3 +/- 22.7 to 13.8 +/- 10.7 days, P < 0.001. Operating room, nursing and x-ray costs decreased, P < 0.002. Hospital costs declined from $14,182 +/- 16,464 to $10,710 +/- 7,332, P < 0.001. Multiple regression showed hospital stay, ICU, operating room time, severity of illness and age to be significant determinants of cost, P < 0.03 for each. Waiting time and number of patients on the waiting list declined significantly as surgical lists increased. Mortality and rate of readmission following discharge were not different between the two groups. CONCLUSIONS: Substantial cost savings can be made by changing practice patterns, without adverse consequences. ICU and hospital length of stay are the most important cost determinants.

Alberta↗
PubMed1993

Aortic valve replacement within a composite graft.

Failure of a bioprosthetic valve within a composite graft presents a challenging surgical problem. A solution to this, as described here, involves leaving a remnant of the failed valve intact within the graft. This forms the annulus to which the new valve is sewn, thus simplifying the operation.

Aortic Valve↗
PubMed1993

Neuroendocrine response to cardiac transplantation.

OBJECTIVE: The neuroendocrine response to heart transplantation was characterized in 11 patients with special reference to long term effects on plasma hormone concentration. DESIGN: Multiple serial measurements of preload, ejection fraction, plasma renin activity (PRA), aldosterone, atrial natriuretic factor (ANF) and catecholamines were made over time. SETTING: Tertiary care cardiac referral, university-based centre. PATIENTS: Eleven adult patients undergoing orthotopic cardiac transplantation were studied. The group consisted of 10 males and one female (mean age 52 +/- 2 years). Eight patients had coronary atherosclerosis, two had idiopathic cardiomyopathy and one had valvular heart disease. All patients were in end-stage heart failure (Canadian Cardiovascular Society class IV) and two also had angina. INTERVENTIONS: Right heart catheterization and hormonal assays in blood were performed simultaneously preoperatively and postoperatively at 24 h, 48 h and during each endomyocardial biopsy. An endomyocardial biopsy to detect rejection was performed weekly for two to four weeks, then every three to four months at one year postoperatively. Hemodynamic measurements included central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP). Ejection fraction was measured in each patient using radionuclide ventriculography preoperatively and serially through the postoperative period. MAIN RESULTS: Following transplantation, transient elevation of intracardiac filling pressures occurred. The CVP and PCWP were elevated at 15 +/- 2 and 17 +/- 1 mmHg, respectively, early postoperatively (ie, days 2 to 30 postsurgery). Late postoperatively (ie, more than 30 days postoperatively), the CVP and PCWP decreased to 8 +/- 1 and 12 +/- 1 mmHg, respectively. Systolic function, as measured by radionuclide ejection fraction, did not change significantly from the early to the late postoperative period (60 +/- 5% early versus 59 +/- 2% late postoperatively). PRA and plasma aldosterone fell in association with the decrease in filling pressures (PRA was 2.4 +/- 0.8 ng/mL/h early versus 1.0 +/- 0.2 ng/ml/h late; plasma aldosterone was 122 +/- 31 pg/mL early versus 103 +/- 16 pg/mL late). Plasma aldosterone levels were similar in the early and late postoperative periods, except during the first day after surgery during which a transient elevation occurred. ANF remained markedly elevated despite the fall in filling pressures (323 +/- 50 pg/mL preoperatively, 360 +/- 33 pg/mL early postoperatively and 322 +/- 31 pg/mL late postoperatively). CONCLUSIONS: The authors conclude that transient cardiac dysfunction occurs following cardiac transplantation with elevation of filling pressures and continued increased activity of the renin-angiotensin-aldosterone system (RAAS) and elevated plasma ANF levels. With return of cardiac function and normalization of filling pressures, the activity levels of the RAAS decrease, but not those of ANF, which remain chronically abnormally elevated. It is not clear whether this persistent elevation of ANF is the result of factors related to the transplant procedure, such as extrinsic denervation or antirejection therapy, among others, or is the persistence of factors acting preoperatively. However, known interactions of cyclosporine with vascular smooth muscle and endothelial cells leading to increased sensitivity to vasopressor hormones and increased circulating levels of endothelin appear as the most likely explanation for the chronic elevation of ANF plasma levels. In this context, ANF may play a key role in moderating the side effects of cyclosporine treatment.

Aldosterone↗