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Biomedical subjects

Y Paz

Publications and source records attributed to Y Paz.

At least 19 recordsLinked to original sources
PubMed2003

Technical aspects of harvesting the radial artery with the harmonic scalpel.

BACKGROUND: Harvesting the radial artery (RA) with ultrasonic dissection with the Harmonic Scalpel reduces spasm induced by surgical handling. Topical exposure to phentolamine methanesulphonate (Regitine) exerts an additional effect of vasodilatation. METHODS: Between January and December 2002, the RA was harvested as a pediculated vessel with the Harmonic Scalpel in 145 consecutive patients undergoing myocardial revascularization. A fasciotomy of the pedicle was performed after harvest ing. A composite graft with the reverse free RA on the in situ left internal thoracic artery (ITA) was prepared before the construction of distal coronary anastomoses. The RA was then placed in a syringe filled with Regitine (0.07 microg/mL) for 10 minutes. \par RESULTS: The mean number of grafts/patient was 3.0. The mean number of RA anastomoses was 2.0/patient. Left ITA free flow was 105 +/- 34 mL/min. Regitine increased the RA free flow from 60 +/- 35 mL/min to 82 +/- 30 mL/min (P <.05). Fourteen patients underwent postoperative coronary angiography. All RA anastomoses were patent. CONCLUSION: The compound effect of RA harvesting with the Harmonic Scalpel and topical treatment with the alpha- blocking agent Regitine increases the RA free flow and significantly decreases intraoperative spasticity.

Aged↗
PubMed2002

Pretreatment with alpha-adrenergic blockers for prevention of radial artery spasm.

BACKGROUND: Radial artery (RA) conduits are prone to early vasospasm. Current intraoperative treatment with papaverine fails to inhibit postoperative RA constriction. Pretreatment with topical a-antagonist solutions can inhibit RA vasoconstriction and cause dilatation for a longer period than achieved with papaverine. METHODS: In 10 patients undergoing myocardial revascularization, the radial artery was harvested as a skeletonized vessel. A composite graft with reverse free RA on an in situ left internal thoracic artery was prepared before construction of distal coronary anastomoses. The RA pedicle was then put in a small syringe filled with Regitine (phentolamine methansulphonic, 0.07 mg/mL) ("Jacuzzi") and warmed by immersing the container in a warm saline bath for 8 to 15 minutes. The RA free flow was measured before and after topical treatment with Regitine. RESULTS: The mean number of grafts per patient was 2.9 (range 2 to 4). The mean number of radial anastomoses was 1.8 per patient. Left internal thoracic artery free flow was 110 +/- 29 mL/min. Regitine increased radial free flow from 49 +/- 35 to 77 +/- 30 mL/min (p < 0.01). Five patients underwent postoperative coronary angiography. All radial anastomoses were patent. CONCLUSIONS: Topical treatment of RA with Regitine increases RA free flow and is an effective intraoperative means of decreasing RA spasticity.

Adrenergic alpha-Antagonists↗
PubMed2002

[Dynamic cardiomyoplasty].

The high prevalence of end-stage heart failure and its influence on the quality of life, force the medical community to seek effective therapeutic modalities. Heart transplantation is the accepted therapy for such patients, nevertheless, a significant percentage of patients do not reach transplantation due to the shortage of donors. Therefore, the establishment of surgical alternatives is very important. Dynamic cardiomyoplasty is accepted as an alternative to heart transplantation. In this technique skeletal muscle is wrapped around the heart and stimulated synchronously with the heart itself. We describe the present status of this procedure.

Cardiomyoplasty↗
PubMed2001

Effect of age on outcome of bilateral skeletonized internal thoracic artery grafting.

BACKGROUND: Elderly patients are considered to be at higher risk for coronary artery bypass grafting. Surgical techniques of arterial myocardial revascularization without vein grafts were primarily reserved for the young. This report evaluates the impact of age on the outcome of 634 consecutive patients who underwent double skeletonized internal thoracic artery grafting between April 1996 and December 1997. METHODS: Patients were stratified into five age groups: One hundred ninety-six were less than 60 years of age, 98 between 60 and 65 years, 132 between 65 and 70 years, 116 between 70 and 75 years, and 92 were older than 75 years. The groups did not differ with regard to preoperative risk factors. RESULTS: Hospital mortality was 2.5% (n = 16). Mortality of urgent and elective operations was 1.6%, and that of emergency operations was 9.7% (p < 0.001). There were 7 (1.1%) myocardial infarctions, 9 strokes (1.4%), and 10 deep sternal wound infections (1.6%). Using the Mantel-Haenszel test, there was no relation between age and hospital mortality, myocardial infarctions, strokes, or sternal infections. A correlation was found between advanced age and early unfavorable events (6.7%, 7.2%, 12.9%, 15.5%, and 15.2% in corresponding age groups, p < 0.003), and late mortality (0.6%, 1%, 1.5%, 4.3%, and 9.8%, respectively, p < 0.01). However, early return of angina was lower (2.6%, 1%, 0.8%, 0.9%, and 0%, p < 0.06). CONCLUSIONS: This retrospective, nonrandomized study suggests that older age is not a risk factor for operative mortality in patients undergoing coronary artery bypass grafting with double skeletonized internal thoracic arteries. Apart from avoiding morbidity associated with leg incisions, older patients showed an interesting trend toward lower rates of angina return. Older patients, however, sustained increased perioperative morbidity and late mortality rates.

Actuarial Analysis↗
PubMed2001

Arterial myocardial revascularization with in situ crossover right internal thoracic artery to left anterior descending artery.

BACKGROUND: The extra length obtained by skeletonizing the internal thoracic arteries (ITAs) enables versatile use of in situ bilateral ITAs for coronary artery bypass grafting, as the longer skeletonized right ITA more easily reaches the anastomotic site on the left anterior descending coronary artery. METHODS: Between April 1996 and November 1999, 365 consecutive patients underwent revascularization with bilateral in situ ITAs (29% of 1,250 grafting procedures performed with both ITAs in our department during this period). The right ITA was routed anterior to the aorta to graft the left anterior descending coronary artery, and the in situ left ITA was used to graft circumflex branches. Right coronary artery branches were grafted with right gastroepiploic artery or saphenous vein graft. The right ITA crossed the midline above the aorta at the most cranial point to avoid damage in case of a repeat sternotomy in the future. RESULTS: The operative mortality rate was 2.2% (8 patients). Postoperative morbidity included seven strokes (1.9%), eight sternal wound infections (2.2%), and four perioperative myocardial infarctions (1.1%). Follow-up (6 to 49 months) of 97% of hospital survivors showed a return of angina in 3%. Postoperative coronary angiography (22 patients) revealed a 95% patency rate of both ITAs. One-year and 4-year survival rates (Kaplan-Meier) were 95% and 92.4%, respectively. Important predictors of an early unfavorable event were chronic obstructive pulmonary disease, old age (> or = 70 years), emergency operation, and diabetes. Chronic obstructive pulmonary disease was the only independent predictor of sternal wound infection (odds ratio, 15; 95% confidence interval, 2.8 to 80). It also predicted decreased late survival (hazard ratio, 8.3; 95% confidence interval, 3 to 21.5). CONCLUSIONS: With skeletonized dissection of ITAs, the right ITA easily reaches the left anterior descending coronary artery for left-sided arterial revascularization with in situ bilateral ITAs. This procedure is safe, but we recommend avoiding its use in patients with chronic obstructive pulmonary disease.

Aged↗
PubMed2001

Variables associated with meconium aspiration syndrome in labors with thick meconium.

OBJECTIVE: To examine the possible maternal and fetal variables associated with meconium aspiration syndrome in labors with thick meconium. STUDY DESIGN: The fetal heart rate tracings, cord pH, Apgar scores and maternal risk factors were evaluated in singleton pregnancies with vertex presentation and thick meconium in labor. The study included 33 consecutive fetuses which developed a moderate or severe meconium aspiration syndrome and 104 consecutive fetuses which had a favorable outcome. RESULTS: Significant differences between fetuses with meconium aspiration syndrome and healthy fetuses were found in the following parameters: baseline FHR (154+/-17 vs. 136+/-10, P<0.0001), small accelerations/30 min (1.47+/-1.52 vs. 3.04+/-1.2, P<0.0001), large accelerations/30 min (1.46+/-1.96 vs. 3.5+/-2.31, P<0.0003), decelerations/30 min (4.9+/-3.9 vs. 2.4+/-2.1, P<0.0034), number of fetuses with reduced beat-to-beat variability (9/33 vs. 0/104, P<0.0001), cord pH (7.21+/-0.09 vs. 7.33+/-0.08, P<0.0013) and Apgar scores at 1 min (5+/-2 vs. 8+/-1, P<0.0001) and Apgar scores at 5 min (8+/-2 vs. 9.7+/-0.6, P<0.0001). Maternal risk factors were found in two of 33 sick infants and in 13 of 104 healthy infants. CONCLUSION: Thick meconium by itself is not associated with adverse fetal outcome. However, the incidence of meconium aspiration syndrome increases in cases of a non-reassuring FHR.

Apgar Score↗
PubMed2001

Interaction between paracrine tumor necrosis factor-alpha and paracrine angiotensin II during myocardial ischemia.

OBJECTIVES: The purpose of this study was to explore interactions between paracrine angiotensin II (Ang-II) and tumor necrosis factor-alpha (TNF-alpha) during myocardial ischemia. BACKGROUND: Ischemic myocardium releases significant amounts of TNF-alpha. This paracrine release correlated with postischemic myocardial injury. Other studies showed myocardial protection obtained by the use of angiotensin-converting enzyme inhibitors (i.e., captopril) and the Ang-II type 1 receptor antagonist losartan after ischemia. The possibility that these agents decrease TNF-alpha synthesis has not yet been investigated. METHODS: Using the modified Langendorff model, isolated rat hearts underwent either 90 min of nonischemic perfusion (control group) or 1 h of global cardioplegic ischemia. In both groups, either captopril (360 micromol/liter) or losartan (182.2 micromol/liter) was added before ischemia. The hearts were assayed for messenger ribonucleic acid (mRNA) expression and effluent TNF-alpha levels. In addition, cardiac myocytes were incubated in cell culture with Ang-II. RESULTS: After ischemia, TNF-alpha mRNA expression intensified from 0.63 +/- 0.06 (control group) to 0.92 +/- 0.12 (p < 0.03), and effluent TNF-alpha levels were 711 +/- 154 pg/ml. The TNF-alpha mRNA expression declined to 0.46 +/- 0.07 (p < 0.01) and 0.65 +/- 0.08 (p < 0.02) in captopril- and losartan-treated hearts, respectively. Effluent TNF-alpha was below detectable levels. Concentrations of TNF-alpha in supernatants of incubated cardiac myocytes treated with 10 and 50 nmol/liter of Ang-II were 206.0 +/- 47.0 pg/ml and 810 +/- 130 pg/ml, respectively (p < 0.004). When pretreated with 700 micromol/liter of losartan, TNF-alpha was below detectable levels. CONCLUSIONS: This study presents an original explanation for previously reported myocardial protection after ischemia, obtained by the use of captopril and losartan. These drugs reduce TNF-alpha synthesis, providing strong evidence of active interactions between paracrine TNF-alpha and Ang-II in the evolution of the ischemic cascade.

Angiotensin II↗
PubMed2001

Vasoactive response of different parts of human internal thoracic artery to isosorbide-dinitrate and nitroglycerin: an in-vitro study.

OBJECTIVE: The left internal thoracic artery (LITA) is the most important graft for coronary artery bypass grafting (CABG). Its distal region is, however, prone to vasospasm. The effect of nitroglycerin (NTG) and isosorbide-dinitrate (ISDN) on different segments of this region was studied. METHODS: Rings of three segments of the LITA were studied: 6-9 mm proximal to the bifurcation (part A); 1-3 mm proximal to the bifurcation (part B); and 3-6 mm distal to the bifurcation (part C). After baseline, maximal contraction of the rings was achieved using 60 mmol/l of KCl, they were exposed to increasing doses of ISDN and NTG (10-100 microg/ml), and dose-response curves were recorded. RESULTS: The contractile response of part A to KCl was significantly lower than that of parts B and C (1.87+/-0.25 versus 4.05+/-0.39 and 7.64+/-0.54 g, respectively; P<0.001). Both nitrates inhibited the contractile response in a concentration-dependent manner. The relaxing effects of both nitrates on part A was most pronounced (P<0.01), with the effect of ISDN being higher than that of NTG (P<0.01). CONCLUSIONS: The region 6-9 mm proximal to the LITA bifurcation is less prone to vasospasm, and has greater relaxation responses to ISDN and NTG than the more vasospastic distal parts of the LITA. We recommend avoiding the use of the very distal part of this artery during CABG, and to use high doses of ISDN rather than NTG as an anti-spastic measure.

Analysis of Variance↗
PubMed2001

Composite arterial grafting with double skeletonized internal thoracic arteries.

OBJECTIVES: Composite arterial grafting is a surgical technique for arterial myocardial revascularization, in which free arterial conduits are proximally anastomosed end-to-side to an intact internal thoracic artery (ITA). This report describes technical aspects and results of composite grafting using bilateral skeletonized ITAs. METHODS: From April 1996 to February 1999, 1057 patients underwent coronary artery bypass grafting (CABG) using bilateral skeletonized internal thoracic arteries. In 600 of them (57%), composite arterial grafting was performed. There were 452 men and 148 women. The mean age was 69 +/- 7 years. Two-hundred and six patients (34%) were diabetics, 84 (14%) had severe left ventricular dysfunction (ejection fraction of < 35%), and 26 (4.3%) underwent emergency operations. In 574 patients, the right ITA was used as a free graft connected to the in-situ left ITA. In 26, the free left ITA was attached to the in-situ right ITA, and in 38, mini-composite grafts (free distal left ITA on the left ITA, or free distal right ITA on the right ITA) were constructed. The average number of grafts was 3.0/patient (range, 2--6). RESULTS: The operative mortality was 2.8% (n = 17), and there were ten (1.7%), deep sternal wound infections. The mean follow-up was 25 months (range, 14--36 months). The 3-year survival was 92.5%. Ninety-seven percent of the surviving patients were angina-free. CONCLUSIONS: We currently perform this surgery routinely in most patients referred for CABG, and regard bilateral skeletonized internal thoracic arteries as the most appropriate arterial conduits for the composite technique.

Adult↗
PubMed2001

Hypotensive reactions associated with transfusion of bedside leukocyte-reduction filtered blood products in heart transplanted patients.

Severe hypotensive reactions that occur during transfusions of blood products to non-transplanted patients were recently linked to the use of bedside leukocyte-reduction filters, sometimes in association with angiotensin-converting enzyme (ACE) inhibitor treatment. We present the first report of such reactions in patients who underwent orthotopic heart transplantation. Fourteen (47%) of the 30 transfused patients experienced severe hypotensive reaction during filtered transfusion of at least 1 unit of blood product, with a total of 24 episodes. Eleven (79%) of these patients were treated pre-operatively with ACE inhibitors.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Bilateral skeletonized internal thoracic artery grafts in patients with diabetes mellitus.

OBJECTIVE: Increased risk of deep sternal infections has prohibited routine bilateral internal thoracic artery grafting in diabetic patients. The technique for harvesting the skeletonized internal thoracic artery provides the potential to minimize this risk. The purpose of this study was to compare the outcome of bypass grafting with bilateral skeletonized internal thoracic arteries in diabetic and nondiabetic patients. METHODS: From May 1996 to April 1998, 231 consecutive diabetic and 534 nondiabetic patients underwent bilateral skeletonized internal thoracic artery grafting. Mean age was 66 years. Compared with the nondiabetic group, the diabetic group comprised more women (29% vs 18%, P =.001), had a greater prevalence of hypertension (53% vs 44%, P =.019) and congestive heart failure (20% vs 14%, P =.016), but a lower prevalence of preoperative acute myocardial infarction (26% vs 34%, P =.027). RESULTS: Operative mortality of diabetic patients was comparable with that of nondiabetic patients (3% vs 2.6%). The two groups also had similar occurrences of deep sternal infection (2.6% vs 1.7%, respectively, P =.40). Deep sternal infection was significantly more prevalent in obese, diabetic women (3/20 = 15%) than in diabetic patients without this combination of risk factors (3/211 = 1.4%, P <.0001) (odds ratio 11.1, confidence interval 2.1-59.4). Diabetic patients also had a higher incidence of stroke (3.5% vs 0.9%, P =.014). Three-year actuarial survival of diabetic patients was lower (91.3% vs 94.7%, P =.083). CONCLUSIONS: Bilateral skeletonized internal thoracic artery grafting is a good surgical revascularization option in diabetic patients. Operative mortality and prevalence of sternal infection are comparable with those of nondiabetic patients. However, the risk of sternal infection in obese diabetic women is high, and for them we advocate the use of a single artery instead of bilateral internal thoracic arteries.

Aged↗
PubMed2000

Structure of GATE-16, membrane transport modulator and mammalian ortholog of autophagocytosis factor Aut7p.

The GATE-16 protein participates in intra-Golgi transport and can associate with the N-ethylmaleimide-sensitive fusion protein and with Golgi SNAREs. The yeast ortholog of GATE-16 is the autophagocytosis factor Aut7p. GATE-16 is also closely related to the GABA receptor-associated protein (GABARAP), which has been proposed to cluster neurotransmitter receptors by mediating interaction with the cytoskeleton, and to the light chain-3 subunit of the neuronal microtubule-associated protein complex. Here, we present the crystal structure of GATE-16 refined to 1.8 A resolution. GATE-16 contains a ubiquitin fold decorated by two additional N-terminal helices. Proteins with strong structural similarity but no detectable sequence homology to GATE-16 include Ras effectors that mediate diverse downstream functions, but each interacts with Ras by forming pseudo-continuous beta-sheets. The GATE-16 surface suggests that it binds its targets in a similar manner. Moreover, a second potential protein-protein interaction site on GATE-16 may explain the adapter activity observed for members of the GATE-16 family.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Technical aspects of double-skeletonized internal mammary artery grafting.

BACKGROUND: Bilateral internal mammary artery (IMA) grafting is performed to provide complete arterial myocardial revascularization with the intention of decreasing postoperative return of angina and the need for reoperation. We present here technical views of double-skeletonized IMA grafting, and evaluate its clinical outcome. METHODS: Skeletonized IMA is harvested gently with scissors and silver clips, without use of cauterization, and embedded in a small syringe filled with papaverine. Three strategies for arterial revascularization were employed in 762 consecutive patients: (1) the cross arrangement (242 patients, 32%), where the in situ right internal mammary artery (RIMA) is used for the left anterior descending artery (LAD), in situ left internal mammary artery (LIMA) to circumflex marginal branches and the gastroepiploic artery for the right coronary artery (RCA); (2) the composite arrangement (476 patients, 62%), where free IMA is attached end-to-side to the other in situ IMA; and (3) the natural arrangement (44 patients, 6%), where the in situ RIMA is connected to the RCA and in situ LIMA to LAD. Mean age was 66 years (range 30 to 92). Two hundred ninety-two patients (38%) were older than 70, and 229 (30%) were diabetic. RESULTS: Operative mortality was 2.5% (n = 19). The mortality of urgent and elective cases was 1.2% (8 of 663), and that of emergency operation was 11% (11 of 99). There were 9 (1.2%) perioperative myocardial infarctions, and 10 patients (1.3%) sustained strokes. Sternal wound infection occurred in 14 (1.8%). CONCLUSIONS: The three strategies described here provide the surgeon with the versatility required for arterial revascularization with bilateral IMAs in most patients referred for coronary artery bypass grafting.

Adult↗
PubMed2000

Computerized analysis of fetal heart rate after maternal glucose ingestion in normal pregnancy.

OBJECTIVE: To examine the effect of maternal oral glucose ingestion on antepartum FHR indices in normal pregnancies at term. STUDY DESIGN: A prospective study was performed on 44 non-laboring healthy women with normal singleton pregnancy at 37-40 weeks gestation. All women had a normal oral glucose tolerance test at 24-28 weeks gestation. FHR was recorded with the Sonicaid Fetal Monitor System (Oxford 8000), for 30 min prior to and 60 min following oral ingestion of 50 g of glucose in the study group of 27 women, and following water ingestion in a control group of 17 women. RESULTS: All pregnancies had a normal outcome. The maternal blood glucose levels before and 30 and 60 min after glucose ingestion were 70+/-14, 107+/-121, and 106+/-22 mg/dl, respectively (P<0.001). A significant negative correlation was found between the changes in maternal blood glucose levels 30 min after glucose ingestion and the changes in the number of large FHR accelerations at 30 and 60 min after glucose ingestion (r=-0.44, P<0.01 and r=-0.42, P<0.01, respectively). A significant correlation was found between the changes in maternal blood glucose levels 30 min after glucose ingestion and changes in episodes of low FHR variation at this time period (r=0.45, P<0.01). No significant changes in any of the FHR variables were noted in the control group. CONCLUSION: In normal pregnancies FHR indices of variation tend to decrease after maternal oral ingestion of glucose.

Blood Glucose↗
PubMed2000

Emergency myocardial revascularization for acute myocardial infarction: survival benefits of avoiding cardiopulmonary bypass.

OBJECTIVE: Emergency coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI) is associated with increased operative mortality. It has been suggested that this mortality might be reduced by performing the operation without cardiopulmonary bypass (CPB). METHODS: Between January 1992 and April 1998, 77 patients underwent emergency CABG within 48 h of AMI. Thirty seven were operated on with CPB, and 40 without CPB. The two groups were similar regarding age, gender, left-ventricular ejection fraction (EF) and preoperative use of intra-aortic balloon pump (IABP; 50%). The mean number of grafts/patient was 3 in the CPB group, and 1.9 in the No-CPB group (P<0.0001). RESULTS: Operative mortality in the CPB group was 24% (nine of 37) compared to 5% (two of 40) without CPB (P=0.015). Follow-up ranged between 6 and 66 months. There were no late deaths in the CPB group compared to nine (22%) in the No-CPB group (P<0.0066). Patients operated on with CPB had lower rates of recurrent angina (0 versus 15%; P=0.04) and re-interventions (0 versus 15%; P=0.04). CONCLUSIONS: Our experience suggests that CABG without CPB is the preferred method of myocardial revascularization, due to the fact that it carries lower mortality than CABG with CPB. The trade-off includes increased rates of recurrent angina, re-interventions and late mortality.

Aged↗