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Biomedical subjects

D J Nikas

Publications and source records attributed to D J Nikas.

9 recordsLinked to original sources
PubMed2000

"Cobrahead" graft for intercostal artery implantation during descending aortic replacement.

A technique for a separate sidearm graft ("cobrahead") to facilitate reattachment of intercostal arteries in descending aortic replacement is described. The technique allows for very prompt restoration of spinal cord blood flow (via a Y attachment from the arterial perfusion circuit). The technique permits a simple, quick, and fully accessible anastomosis, technically more facile than the traditional side-to-side anastomosis. None of 7 patients treated with this technique had early or late paraplegia. Preliminary computed tomographic follow-up scans confirm patency of the cobrahead graft.

Anastomosis, Surgical↗
PubMed1998

Origin of angina pectoris in patients with high-grade single-vessel coronary artery stenosis undergoing percutaneous transluminal coronary angioplasty.

This study shows that in patients with subtotal (95% to 99%) coronary artery stenosis, the presence of myocardial ischemia is dictated primarily by the presence and degree of coronary collateral flow, with anterograde flow participating little, if at all, in the origin of myocardial ischemia and angina pectoris. Conversely, in patients with severe but not subtotal coronary artery stenosis (70% to 94%), both reduced anterograde flow and coronary collateralization contribute to the evolution of myocardial ischemia and angina pectoris.

Adult↗
PubMed1998

Topical hypothermia: ineffective and deleterious as adjunct to cardioplegia for myocardial protection.

BACKGROUND: Topical hypothermia, an early method developed for myocardial protection by virtue of its reduction of cardiac metabolic rate, is not without sequelae such as phrenic nerve paralysis and pulmonary complications. METHODS: The hospital records of 505 nonrandomized consecutive patients undergoing coronary artery bypass grafting between 1991 and 1995 at the University of South Alabama were reviewed to evaluate the effectiveness of topical hypothermia and its relationship to pulmonary complications. Group A included 191 patients between 1991 and 1992 who received systemic hypothermia and topical hypothermia with iced slush in addition to cold blood cardioplegia. Group B included 314 patients between 1993 and 1995 who received systemic hypothermia and intermittent cold blood cardioplegia without iced slush. RESULTS: Myocardial temperature mapping did not reveal any difference between the two groups. Postoperative cardiac morbidity, manifested as intraaortic balloon use, low cardiac output, inotrope use, and perioperative myocardial infarction, was decreased in group B, but the difference failed to achieve statistical significance. Mortality (group A, 3.14%; group B, 3.82%) and rates of significant morbidity such as sternal infection, stroke, reoperation for bleeding, renal failure, and prolonged ventilation were comparable between the two groups. However, there was a statistically significant difference in the incidence of diaphragmatic paralysis between group A and group B. Group A had a 25% incidence of diaphragmatic paralysis on the first postoperative day, 18% on the 15th postoperative day, and 8% at 6 months, as opposed to group B, which had incidences of 2% on the first postoperative day, 1% on the 15th postoperative day, and 1% at 6 months (p < 0.001). Also, there was a significant difference in incidence of pleural effusions (60% versus 25%) and rate of thoracentesis (25% versus 8%) between groups A and B (p < 0.0001). CONCLUSIONS: We conclude that topical hypothermia did not offer any additional cardioprotective benefit above systemic hypothermia and cold blood cardioplegia alone in coronary bypass patients, but significantly increased the incidence of diaphragmatic paralysis and associated pulmonary complications.

Coronary Artery Bypass↗
PubMed1997

Symptomatic reinfarctation of a previously silent myocardial region four months after successful reperfusion--a case report.

Coronary collateral circulation helps to preserve myocardial perfusion distal to severely stenotic or totally obstructed coronary arteries. The presence or absence of angina pectoris and the state of myocardial function depend on the extent of collateralization and its functional contribution to myocardial blood flow. Clinical and experimental observations have suggested that newly developed collaterals usually remain even after successful revascularizaton. The authors present a case of a patient with extensive intercoronary collaterals and hibernating myocardium after an acute inferior wall myocardial infarction who underwent successful percutaneous transluminal coronary angioplasty of a totally obstructed, dominant right coronary artery and then experienced extensive reinfarction following reocclusion 4 months later. This case demonstrates failure of extensive collaterals to prevent acute myocardial infarction.

Adult↗
PubMed1996

Use of a national data base to assess perioperative risk, morbidity, mortality, and cost savings in coronary artery bypass grafting.

To show the usefulness of the Society of Thoracic Surgeons (STS) National Database in providing clinical and cost-related outcome data, we studied 297 consecutive patients who had isolated coronary artery bypass grafting (CABG) and who were assigned to either a "fast track" or traditional track. The observed overall mortality rate was 2.7%. The predicted mortality based on preoperative risk factors was 4.7%. Before the initiation of a "fast-track" protocol and critical pathways, the average length of stay was 8.2 days and the average cost of uncomplicated isolated CABG was $18,476. The length of postoperative stay and the cost decreased to 6.0 days and $12,427, respectively, with the application of a fast-track protocol (when appropriate) and critical pathways without affecting clinical outcomes. Use of the STS National Database provided rapid and reassessing evidence that survival and quality of care were not compromised with implementation of a cost-saving fast-track protocol and critical pathways.

Aged↗
PubMed1996

Delayed posttraumatic tamponade.

Delayed cardiac tamponade is a rare phenomenon with two primary causes: delayed hemorrhage after an acute injury or delayed pericarditis with effusion. We present a case of cardiac tamponade 4 weeks after injury, with findings compatible with delayed hemorrhage and pericarditis. Our case emphasizes the need for follow-up of patients with penetrating chest trauma for several months after injury; echocardiography should be used if symptoms of tamponade appear.

Adult↗
PubMed1989

Effect of large-bowel obstruction on colonic blood flow. An experimental study.

The effect of subacute large-bowel obstruction on the mesenteric circulation was studied in a chronic dog model. Colonic obstruction was produced 40 cm distal to the ileocolic sphincter. Five days later, gut blood flow was measured with 15 microns microspheres, together with hemodynamic and metabolic values. Two other groups provided comparative data: unoperated animals to measure baseline values and sham-operative controls. With adequate hydration, hemodynamic and metabolic values remained stable in the experimental group. There was a two-fold increase (P less than 0.05) in blood flow in the dilated colon proximal to the obstruction site, whereas blood flow to the other organs remained unchanged. These results have relevance for the hemodynamic management and use of primary anastomosis in patients with large-bowel obstruction. Furthermore, these data might implicate increased local bowel blood flow as a contributory factor to the poorer long-term prognosis found in patients with large-bowel cancer presenting with intestinal obstruction.

Animals↗