Biomedical subjects

T Mycyk

Publications and source records attributed to T Mycyk.

9 recordsLinked to original sources

PubMed2001

Cardiac surgery increases the activity of matrix metalloproteinases and nitric oxide synthase in human hearts.

OBJECTIVES: Heart function is variably impaired after cardiopulmonary bypass. We hypothesized that, similar to other myocardial injury states, cardiopulmonary bypass leads to enhanced activity of nitric oxide synthase and matrix metalloproteinases. METHODS: We obtained right atrial biopsy specimens and plasma samples at the onset and termination of cardiopulmonary bypass in 10 patients. Biopsy specimens were analyzed for nitric oxide synthase activity by using a citrulline assay, whereas plasma and tissue were analyzed for matrix metalloproteinase-9 and matrix metalloproteinase-2 activity by using zymography. Tissue inhibitor of metalloproteinase-4 was analyzed by means of Western blotting. The cellular expression of inducible nitric oxide, endothelial nitric oxide synthase, matrix metalloproteinase-2, and matrix metalloproteinase-9 was determined in right atrial biopsy samples from 3 additional patients by using the appropriate conjugated antibodies. RESULTS: Nitric oxide synthase activity increased from the beginning to the end of bypass (4.46 +/- 1.07 vs 16.77 +/- 4.86 pmol citrulline/mg of protein per minute, respectively; P =.018). Pro-matrix metalloproteinase-9 activity increased in hearts (199 +/- 41 vs 660 +/- 177 density units/mg protein; P =.008) and plasma (14.1 +/- 4.6 vs 52.2 +/- 5.9 density units/mg protein; P =.008). Pro-matrix metalloproteinase-2 activity increased in the heart (201 +/- 23 vs 310 +/- 35 density units/mg protein, P <.05) but not in plasma. Tissue inhibitor of metalloproteinase-4 expression in the heart decreased (1574 +/- 280 vs 864 +/- 153 density units, P =.014). CONCLUSIONS: Cardiopulmonary bypass activates enzymes mediating acute inflammation and organ injury (ie, nitric oxide synthase, matrix metalloproteinase-9, and matrix metalloproteinase-2). Decreased tissue inhibitor of metalloproteinase-4 expression allows relatively unopposed increases in matrix metalloproteinase tissue activity. We postulate that these changes play a role in the pathogenesis of heart dysfunction after bypass surgery.

Aged↗

PubMed1997

Depletion of activated neutrophils by a filter during cardiac valve surgery.

PURPOSE: To determine whether inclusion of a neutrophil-specific filter into the extracorporeal circuit during open heart valve surgery alters postoperative outcomes. METHODS: Convenience sampling of 24 patients undergoing elective open heart valve surgery between July 1993 and June 1994. Patients were randomized to a neutrophil-specific filter (n = 11) or to a standard blood filter (n = 13) during cardiopulmonary bypass. RESULTS: Neutrophil-specific filter diminished (P < 0.02) the expression of CD18, a neutrophil surface adhesion molecule, at I (84.5 +/- 4.2 vs 94.8 +/- 3.8%), 4 (80.0 +/- 4.2 vs 95.1 +/- 3.9%) and 24 hr (75.2 +/- 4.2 vs 98.2 +/- 3.9%) post-operatively compared with standard filter. Total white blood cell count, neutrophil count, and pro-inflammatory cytokines (IL-6, IL-8) were similar between groups at all times. Measured outcomes including: PaO2 cardiac index, ejection fraction, haemodynamic variables, use of inotropes, spirometry (FEV1, FVC), and hospitalization duration were similar between groups. CONCLUSIONS: Inclusion of the neutrophil filter during open heart valve surgery selectively depletes activated neutrophils. There were no other detectable differences between the two groups and the use of a neutrophil-specific filter in routine clinical practice for patients undergoing open heart valve surgery is not supported.

Adult↗

PubMed1997

Respiratory outcomes with early extubation after coronary artery bypass surgery.

OBJECTIVE: Aortocoronary bypass surgery has undergone recent changes, promoting the concept of "fast tracking," in which patients are extubated and discharged postoperatively at an accelerated pace compared with previous historic patterns. Postoperative respiratory function and complications have not been previously studied in patients selected for "fast tracking." DESIGN: Matched retrospective cohort study. SETTING: Referral university teaching hospital. PATIENTS: Thirty-one patients who were compared with a retrospective matched cohort of 112 patients. Matching was based on forced vital capacity, age, and gender. INTERVENTIONS: Respiratory physiological outcomes defined as pneumonia, postoperative pulmonary spirometry, chest x-ray atelectasis or lobar collapse, and gas exchange were compared. MAIN RESULTS: The increase in atelectasis score compared with preoperative (0 = no atelectasis, 4 = lobar collapse) was higher (p < 0.01) on the day of extubation in the late extubation group (4.1 +/- 1.4) compared with the early extubation group (2.6 +/- 1.3). These chest radiographic findings were not related to pain (0 to 10 visual analog scalei, which were equivalent between groups (4.0 +/- 2.3 v 4.2 +/- 1.6). The decreases in spirometry on postoperative day 5 (FVC 1.15 +/- 0.42 v 0.86 +/- 0.54 liters; FEV1 0.92 +/- 0.38 v 0.59 +/- 0.50 liters) were greater (p < 0.001) in the late extubation group. A significantly (p < 0.001) greater decrease in FEV1/FVC ratio in the late extubation group (3.25 +/- 0.87 v -1.6 +/- 1.11%) was indicative of greater airway obstruction. Fluid balance until extubation was greater in the late extubation group (4.0 +/- 2.1 v 1.4 +/- 1.2 liters). CONCLUSIONS: Differences in chest radiographs in the late extubation group at the time of extubation may be related to greater use of fluids or increased airway obstruction. The rationale of early extubation is based on cost minimization to decrease hospital duration. This article suggests that respiratory physiological outcomes are not worsened in patients who are extubated and discharged early after elective aortocoronary bypass surgery.

Airway Obstruction↗

PubMed1996

Respiratory function after cardiac surgery.

STUDY OBJECTIVE: Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN: Convenience sampling of observational cohort. SETTING: Tertiary care university hospital. PATIENTS: One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS: Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS: Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS: Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Adult↗

PubMed1995

Depletion of neutrophils by filter during aortocoronary bypass surgery transiently improves postoperative cardiorespiratory status.

STUDY OBJECTIVE: To determine whether inclusion of a leukocyte specific filter into the extracorporeal circuit during aortocoronary bypass surgery alters postoperative cardiopulmonary function. DESIGN: Randomized, double-blinded control trial. SETTING: Tertiary care hospital. PATIENTS: Convenience sampling of patients undergoing elective aortocoronary bypass between October 1992 and June 1993. INTERVENTIONS: A total of 32 patients were randomized to a leukocyte specific filter (n = 16) or to a standard blood filter (n = 16) during the surgical procedure. MEASUREMENTS AND RESULTS: White blood cell count in the standard filter group (12.2 +/- 3.6 10(9)/L) was higher (p = 0.047) than in the leukocyte filter group (9.9 +/- 2.6 10(9)/L) at 4 h postoperatively but counts were similar (p = 0.063) at 24 h (10.8 +/- 2.7 vs 8.9 +/- 2.6 10(9)/L, respectively). Leukocyte activation assessed by chemiluminescence was similar between groups at all measurement periods. We noted transient improvements (p < 0.05) in intrapulmonary shunt (19 +/- 50% vs 24 +/- 9%) and mean blood pressure (85 +/- 8 vs 76 +/- 9 mm Hg, respectively) in the leukocyte filter group compared with the standard filter group, respectively. Otherwise there were no differences noted between groups. CONCLUSIONS: Inclusion of a leukocyte filter during cardiopulmonary bypass caused transient cardiorespiratory improvement that was lost within 24 h and did not offer any significant clinical benefits.

Aged↗

PubMed1989

Dissection of ascending thoracic aorta complicated by cardiac tamponade.

Two cases of cardiac tamponade caused by dissections of the ascending thoracic aorta are described. Despite uneventful induction of anaesthesia one patient exsanguinated following sternotomy and release of pericardial tamponade as the resulting increase in blood pressure caused aortic rupture. The second patient was managed with femoral-femoral bypass, propranolol and vasodilators prior to sternotomy to avoid this complication, and he survived. The anaesthetic management of a patient with cardiac tamponade is directed towards maintaining cardiac filling pressures and contractility. When the tamponade is released the sudden increase in cardiac output and blood pressure may cause the already weakened aorta to rupture.

Aged↗

PubMed1989

Ancrod anticoagulation for cardiopulmonary bypass in heparin-induced thrombocytopenia and thrombosis.

Heparin-induced thrombocytopenia and thrombosis was diagnosed in a 50-year-old man undergoing a repeat heart operation after heparinization led to microemboli and an eventual left transmetatarsal amputation. A third heart operation was aborted when anticoagulation with low molecular weight heparin produced intraoperative thrombi. The patient was referred to Toronto where ancrod (Arvin) was used to lower plasma fibrinogen level, allowing successful repair of a ventricular septal defect using cardiopulmonary bypass support. The patient made an uneventful recovery.

Ancrod↗

PubMed1987

A technique for selective graft perfusion during aortocoronary bypass.

A technique is described that provides early reperfusion of acutely ischemic myocardium during the construction of saphenous vein bypass grafts to the coronary arteries. Selective vein graft perfusion provides early and appropriate cooling of the most ischemic zones identified by either electrocardiographic changes or intramyocardial temperature probes and allows warm blood reperfusion during construction of proximal anastomoses. The technique may be applicable to patients who present with acute ischemia and evolving infarction, failed angioplasty, or left main coronary artery stenosis.

Anastomosis, Surgical↗

PubMedDate not supplied

Identification of Chiari's network with transesophageal echocardiography.

A prominent Chiari's network may be difficult to distinguish from pathologic right atrial masses on transthoracic echocardiography. We report a 38-year-old woman who had a cerebrovascular accident. Transthoracic echocardiogram revealed an atrial septal aneurysm and a mobile right atrial mass. This mass was correctly identified as Chiari's network on the basis of the transesophageal echocardiographic findings of a broad base of attachment in the right atrium and filamentous nature of the mass. These findings were confirmed at surgery.

Adult↗