Search PubMed⌕ Search

Biomedical subjects

Costas S Bizekis

Publications and source records attributed to Costas S Bizekis.

6 recordsLinked to original sources
PubMed2004

Vein graft arterialization causes differential activation of mitogen-activated protein kinases.

OBJECTIVE: Vascular injury results in activation of the mitogen-activated protein kinases-extracellular-signal regulated kinases, c-jun N-terminal kinase, and p38(MAPK)-which have been implicated in cell proliferation, migration, and apoptosis. The goal of this study was to characterize mitogen-activated protein kinase activation in arterialized vein grafts. METHODS: Carotid artery bypass using reversed external jugular vein was performed in 29 dogs. Vein grafts were harvested after 30 minutes and 3, 8, and 24 hours, and 4, 7, 14, and 28 days. Contralateral external jugular vein and external jugular vein interposition vein-to-vein grafts were used as controls. Vein graft extracts were analyzed for extracellular-signal regulated kinases, c-jun N-terminal kinase, and p38(MAPK) activation. Proliferating cell nuclear antigen expression was investigated as a parameter of cell proliferation. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling staining and intimal hyperplasia by morphometric examination of tissue sections. RESULTS: Significant intimal hyperplasia was observed at 28 days. Over the time points studied, vein graft arterialization resulted in bimodal activation of both extracellular-signal regulated kinase and p38(MAPK) (30 minutes through 3 hours; 4 days) but did not induce activation of c-jun N-terminal kinase. Proliferating cell nuclear antigen expression increased from days 1 through 28, and apoptosis increased between 8 and 24 hours. CONCLUSION: Vein graft arterialization induces bimodal activation of extracellular-signal regulated kinase and p38(MAPK); however, in contrast with what is described in arterial injury, it does not induce c-jun N-terminal kinase activation. These results provide the first comprehensive characterization of the mitogen-activated protein kinase signaling pathways activated in vein graft arterialization and identify mitogen-activated protein kinases as potential mediators of vein graft remodeling and subsequent intimal hyperplasia.

Animals↗
PubMed2003

Off-pump coronary artery bypass grafting reduces mortality and stroke in patients with atheromatous aortas: a case control study.

BACKGROUND: Patients with severe atheromatous aortic disease (AAD) who undergo coronary artery bypass (CABG) have an increased risk of death and stroke. We hypothesized that in these high risk patients, off-pump coronary artery bypass (OPCAB) technique is associated with lower morbidity and mortality. METHODS AND RESULTS: Between June 1993 and January 2002, 5737 patients undergoing CABG had routine intra-operative TEE with 913 (15.9%) found to have severe AAD in the aortic arch or ascending aorta. Of these, 211 patients who underwent OPCAB were matched with 211 on-pump CABG patients by age, ejection fraction, history of stroke, cerebrovascular disease, diabetes, renal disease, nonelective operation, and previous cardiac surgery. Hospital mortality was 11.4% (24/211) for on-pump CABG and 3.8% (8/211) for OPCAB (P=0.003). Multivariate analysis revealed that increased mortality was associated with on-pump CABG (P=0.001), acute MI (P=0.03), number of grafts (P=0.01), age (P=0.01), history of stroke or cerebrovascular disease (P=0.04), CHF (P=0.02), and peripheral vascular disease (P=0.03). Multivariate analysis showed that OPCAB technique was associated with decreased stroke (P=0.05). Freedom from any complication was 78.7% for on-pump CABG and 91.9% for OPCAB (P<0.001). At 36 month follow-up multivariate analysis revealed that increased mortality was associated with age (P=0.001), previous MI (P=0.03), and renal disease (P=0.04), whereas increased survival was associated with increased number of grafts (P=0.001) and OPCAB (P=0.01). CONCLUSIONS: OPCAB surgery in patients with severe AAD is associated with lower risk of death, stroke and complications and improved mid-term survival. Routine intra-operative TEE allows identification of these patients and directs choice of appropriate surgical technique.

Aged↗
PubMed2003

Routine intraoperative transesophageal echocardiography identifies patients with atheromatous aortas: impact on "off-pump" coronary artery bypass and perioperative stroke.

BACKGROUND: Patients with severe atheromatous aortic disease (AAD) undergoing coronary artery bypass grafting (CABG) have increased operative risks. The "off-pump" CABG (OPCAB) technique was evaluated in patients given the diagnosis of severe AAD by routine transesophageal echocardiography. METHODS: A total of 5737 patients underwent CABG, with 913 having transesophageal echocardiography findings of severe AAD. Of the patients with severe AAD, 678 (74.3%) had conventional CABG and 235 (25.7%) had OPCAB. RESULTS: Hospital mortality was 8.7% for conventional CABG and 5.1% for OPCAB (P =.08). Multivariate analysis revealed that increased mortality was significantly associated with acute myocardial infarction, conventional CABG, age, renal disease, history of stroke, and ejection fraction < 30%. Neurologic complications occurred in 6.3% of patients undergoing CABG and in 2.1% undergoing OPCAB (P =.01). Freedom from any complication was significantly greater with OPCAB. CONCLUSION: Routine intraoperative transesophageal echocardiography identifies patients with severe AAD. In these patients, OPCAB technique is associated with a lower risk of death, stroke, and all complications.

Aged↗
PubMed2002

Evolving techniques for mitral valve reconstruction.

OBJECTIVE: To analyze the effectiveness of new techniques of mitral valve reconstruction (MVR) that have evolved over the last decade, such as aggressive anterior leaflet repair and minimally invasive surgery using an endoaortic balloon occluder. SUMMARY BACKGROUND DATA: MVR via conventional sternotomy has been an established treatment for mitral insufficiency for over 20 years, primarily for the treatment of patients with posterior leaflet prolapse. METHODS: Between June 1980 and June 2001, 1,195 consecutive patients had MVR with ring annuloplasty. Conventional sternotomy was used in 843 patients, minimally invasive surgery in 352 (since June 1996). Anterior leaflet repair was performed in 374 patients, with increasing use over the last 10 years. Follow-up was 100% complete (mean 4.6 years, range 0.5-20.5). RESULTS: Hospital mortality was 4.7% overall and 1.4% for isolated MVR (1.1% for minimally invasive surgery vs. 1.6% for conventional sternotomy; =.4). Multivariate analysis showed the factors predictive of increased operative risk to be age, NYHA functional class, concomitant procedures, and previous cardiac surgery. The 5-year results for freedom from cardiac death, reoperation, and valve-related complications among the 782 patients with degenerative etiology are, respectively, as follows ( >.05 for all end points): for anterior leaflet repair, 93%, 94%, 90%; for no anterior leaflet repair, 91%, 92%, 91%; for minimally invasive surgery, 97%, 89%, 93%; and for conventional sternotomy, 93%, 94%, 90%. CONCLUSIONS: These findings indicate that late results of MVR after minimally invasive surgery and after anterior leaflet repair are equivalent to those achievable with conventional sternotomy and posterior leaflet repair. These options significantly expand the range of patients suitable for mitral valve repair surgery and give further evidence to support wider use of minimally invasive techniques.

Adult↗