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Biomedical subjects

R Astudillo

Publications and source records attributed to R Astudillo.

At least 19 recordsLinked to original sources
PubMed2003

Biphasic pro-thrombotic and inflammatory responses after coronary artery bypass surgery.

Early graft failure after coronary artery bypass grafting (CABG) is related to thrombosis and inflammation in the grafted vessel(s). The time courses of, and relationships between, pro-thrombotic and inflammatory responses to CABG surgery have, however, not been well defined. Fifteen patients undergoing CABG were examined before, and 1 h, 1 day, 7 days, and 3 months after surgery. Cellular markers of platelet and leukocyte activation were monitored by whole blood flow cytometry, and plasma markers of pro-thrombotic and inflammatory responses were analyzed by immunoassays. CABG immediately increased circulating P-selectin-positive platelets, leukocyte CD11b expression, and platelet-leukocyte aggregates (PLAs). Thrombin generation (F1 + 2 levels) and cytokine release [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-8, and IL-10], soluble P-selectin, and soluble E-selectin also increased immediately. These alterations persisted during the first week after surgery, with re-bound increases of circulating activated platelets and PLAs, TNF-alpha, and F1 + 2 on day 7. Platelet and PLA responsiveness to in vitro stimulation was suppressed immediately after CABG, but markedly enhanced 1 week after surgery. After 3 months, plasma soluble P-selectin, F1 + 2, and IL-10, and monocyte CD11b expression were still slightly elevated compared with baseline. In conclusion, CABG induces marked pro-thrombotic and inflammatory responses, which persist for at least 1 week. Platelet activation, platelet reactivity, PLA formation, thrombin generation, and TNF-alpha release show a second peak 1 week after surgery. These findings suggest that intensified and prolonged antithrombotic/inflammatory treatment should be considered after CABG surgery.

Aged↗
PubMed2001

Fewer reoperations and shorter stay in the cardiac surgical ward when stabilising the sternum with the Ley prosthesis in post-operative mediastinitis.

OBJECTIVE: Using the Ley prosthesis, a 0.5mm thick titanium alloy plate for stabilising the sternum, is a new method in the treatment of mediastinitis after open-heart surgery. We report a retrospective analysis of our experience with this device. METHODS: One hundred consecutive cases of post-operative mediastinitis in the period 1992-1997 were reviewed. The primary procedure at reoperation for infection was as follows: 52 patients were treated with the Ley prosthesis and 48 patients underwent other conventional procedures. The choice of the surgical technique depended on the attending surgeon. The prosthesis was used more frequently in patients with sternal dehiscence (P<0.001) but otherwise patients' characteristics were similar in the two groups. As a control population for outcome data, 100 uninfected patients were matched with regard to operative procedure, age, sex and date of surgery. RESULTS: The median hospital stay was 48.5 days in the mediastinitis group vs. 14 days in the control group. The all-cause 90-day mortality in the mediastinitis group was 18% vs. 5% in the control group. The 52 patients treated with the Ley prosthesis had a median length of stay in the cardiac surgery ward for 29 days vs. 41.5 days in the mediastinitis group not treated with the prosthesis (P=0.013). However, when the total length of stay including hospitals outside the cardiac surgery ward was taken into account, the prosthesis did not reduce the length of stay. Only 8/52 patients treated with the prosthesis required further surgery vs. 23/48 patients who were not primarily treated with the prosthesis (P<0.001). The Ley prosthesis had no impact on mortality. CONCLUSION: The Ley prosthesis is a valuable adjunct to the treatment of mediastinitis after open-heart surgery. A shorter stay at the cardiac surgery ward and a reduced need for further surgical procedures were observed when using this prosthesis.

Aged↗
PubMed2001

No effect of L-arginine supplementation on pulmonary endothelial dysfunction after cardiopulmonary bypass.

BACKGROUND: Acetylcholine is an endothelium-dependent vasodilator through the L-arginine-nitric oxide pathway. After ischemia-reperfusion this effect is attenuated, also demonstrated in the pulmonary circulation after cardiopulmonary bypass. Administration of L-arginine has been shown to have a protective effect on endothelial function in reperfusion injury. The aim of the current study was to test the possible effect of L-arginine on the acetylcholine reactivity in the pulmonary circulation after cardiopulmonary bypass. METHODS: Thirty-five patients with ischemic and/or valvular heart disease were investigated in a randomized, double-blinded, placebo-controlled study. The patients were divided into three groups. Group 1: high dose L-arginine (n=10), group 2: low dose L-arginine (n=10), group 3: placebo, no L-arginine, (n=15). The acetylcholine reactivity was tested with measurements of pulmonary vascular resistance before surgery and 1, 2 and 3-4 h after cardiopulmonary bypass. RESULTS: After cardiopulmonary bypass an attenuation of the acetylcholine reactivity over time was observed in all groups, with no differences between groups. CONCLUSION: In the current study L-arginine had no protective effect on the pulmonary endothelium after cardiopulmonary bypass, measured as reactivity to an infusion of acetylcholine.

Acetylcholine↗
PubMed1998

Altered reactivity to acetylcholine in the pulmonary circulation after cardiopulmonary bypass is part of reperfusion injury.

STUDY OBJECTIVE: To investigate whether a time sequence of acetylcholine (ACH) reactivity indicative of endothelial reperfusion injury could be demonstrated in the pulmonary circulation in patients after cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: Operating theater and intensive care unit of a university hospital. PATIENTS: 10 ASA physical status III and IV patients with ischemic or valvular heart disease. INTERVENTIONS: Pulmonary vascular resistance index (PVRI) was measured before and during an infusion of ACH. This procedure was done after induction of anesthesia but before surgery, immediately after weaning from bypass, and at 1 to 1.5 and 4 hours after CPB. MEASUREMENTS AND MAIN RESULTS: ACH caused a decrease in PVRI before (p < 0.01) and directly after CPB (p < 0.05) but not at 1 to 1.5 or 4 hours after bypass. CONCLUSIONS: The maintained reactivity to ACH directly after CPB, followed by no reaction at 1 to 1.5 and 4 hours, was in agreement with experimental findings and indicates endothelial reperfusion injury caused by the period with no blood flow through the pulmonary artery during CPB and subsequent reperfusion.

Acetylcholine↗
PubMed1998

Decreased pulmonary vascular resistance during nasal breathing: modulation by endogenous nitric oxide from the paranasal sinuses.

Nitric oxide is present in high concentration in the human nasal airways. During inspiration through the nose a bolus is transported to the lungs. In a randomized cross-over study the effect of two different patterns of breathing, nasal breathing and mouth breathing, was evaluated in 10 patients (mean age 65 years), breathing room air the morning of the first post-operative day after open heart surgery. Nasal breathing is defined as inspiration through the nose and expiration through the mouth, whilst mouth breathing is the converse of this: inspiration through the mouth and expiration through the nose. Pressure in the pulmonary artery and left atrium or pulmonary artery wedge was measured together with thermodilution cardiac output and arterial and mixed venous oxygenation and acid-base parameters. Pulmonary vascular resistance index (PVRI), venous admixture and alveolar-arterial gradient were calculated. Nasal breathing resulted in a lower PVRI, 256 dyn s cm-5 cm-2 vs. 287 (P < 0.01). The oxygen and carbon dioxide tension and pH of arterial and mixed venous blood, venous admixture and the alveolar-arterial gradient remained unchanged. The decreased level of PVRI during nasal breathing compared to that during mouth breathing supports the notion, that endogenous nitric oxide acts as an airborne messenger to modulate the pulmonary vascular tone during normal breathing.

Cross-Over Studies↗
PubMed1998

Asian and Pacific Islander American HIV community-based organizations: a nationwide survey.

A national survey was conducted to (a) ascertain the status of HIV prevention among community-based organizations targeting APIs in the United States, (b) define technical assistance needs among these organizations, and (c) determine their involvement in the HIV community planning process. Of the 80 surveys sent out, 49 (61%) completed responses were received. Filipinos, Chinese, Vietnamese, Cambodians, and multiracials were the subpopulations targeted the most often, and, not surprising, Tagalog, Cantonese, Mandarin, Vietnamese, Cambodian, Korean and Japanese were the Asian languages most widely in use. Gay men, bisexual men, and youth were targeted most frequently by HIV prevention efforts. Of all the largest ethnic subpopulations, Asian Indian is the only group with no community-based organization that exclusively targets them for HIV prevention. More than 95% of respondents reported conducting some type of evaluation; the size of the budget and organization often determined the evaluation strategies used. Program development, staff development, and program evaluation were the most frequently reported areas of technical assistance requested. A majority of the respondents (79%) reported being involved with the HIV prevention community planning process where APIs were represented on state/local community planning groups, they did not rate the performance of the community planning process highly. We recommend providing technical assistance in fund-raising, program evaluation, and participation in the HIV community planning process.

Asian↗
PubMed1996

Elevated serum levels of S-100 after deep hypothermic arrest correlate with duration of circulatory arrest.

OBJECTIVE: Cerebral damage is a major problem after reconstructive surgery of the aortic arch and the descending aorta. Current protective strategies, including deep hypothermia and retrograde cerebral perfusion, are used to prolong the tolerated duration of circulatory arrest, and the latter may also decrease the possibility of air/particle embolization. The aim of the current study was to investigate whether the neurochemical marker S-100 is related to the duration of circulatory arrest, when the influence of embolic injury has been minimized by the use of retrograde cerebral perfusion during the last part of circulatory arrest. METHODS: Arterial serum levels of S-100 were followed before, during and after reconstructive surgery of the thoracic aorta during deep hypothermic arrest in ten adults. Retrograde cerebral blood perfusion was used during the latter part of the arrest period in eight of the ten patients. Neurologic status was followed daily. RESULTS: All patients survived the operation. The median (range) duration of cardiopulmonary bypass (CPB) was 184.5 (121-386) min. The median duration of circulatory arrest and retrograde cerebral perfusion was 50 (3-118) min and 16 (0-84) min, respectively. S-100 increased from 0.10 (0.02-0.18) microg/l preoperatively to 2.37 (0.64-10.80) microg/l after CPB (P<0.01), followed by a decrease to 0.79 (0.21-2.64) microg/l on the first postoperative day (P<0.01). The duration of circulatory arrest correlated with S-100 levels after CPB (r(S) = 0.71, P<0.05) and even better with the S-100 levels on the first postoperative day (r(S) = 0.83, P<0.01). However, there was no significant correlation between duration of arrest and duration of CPB. The duration of circulatory arrest without retrograde cerebral perfusion correlated well with S-100 levels on the first postoperative day (r(S) = 0.88, P<0.01), but not significantly with S-100 levels after CPB. CONCLUSIONS: S-100 levels after aortic surgery with deep hypothermic arrest correlate with the duration of circulatory arrest, indicating that the duration of circulatory arrest is damaging to the brain despite the use of deep hypothermia and partial retrograde cerebral perfusion. The highest correlation between S-100 and duration of arrest was seen on the first postoperative day. S-100 appears to perform well under clinical circumstances as a sensitive and discriminative marker for neuronal injury.

Adult↗
PubMed1993

Cerebral lactate release after circulatory arrest but not after low flow in pediatric heart operations.

Arteriovenous (jugular bulb) differences in blood lactate were followed throughout the procedure and until 18 hours postoperatively in 17 children undergoing congenital heart operations during profound hypothermia. Transcranial Doppler sonography was used to monitor changes in blood flow velocity in the middle cerebral artery. Ten children had a period of total circulatory arrest (39 +/- 6 minutes) during profound hypothermia (arrest group). Another 7 children had continuous but reduced pump flow (0.6 to 1.2 L/m2) throughout hypothermic cardiopulmonary bypass (low-flow group). The mean age was 7.3 +/- 1.3 months in the arrest group and 7.9 +/- 2.2 months in the low-flow group. The mean time on bypass was 90 +/- 10 minutes in the arrest group and 75 +/- 9 minutes in the low-flow group. The velocity of blood flow in the middle cerebral artery decreased significantly (p < 0.05) in both groups to less than 50% of the preoperative level during hypothermia and increased during and after rewarming. Differences in blood lactate level were significantly less than zero (p < 0.05) from the start of rewarming until 3 hours after the end of cardiopulmonary bypass in the arrest group, whereas differences in blood lactate level remained close to zero in the low-flow group. We conclude that circulatory arrest during profound hypothermia is followed by a period with release of lactate from the brain, indicating anaerobic cerebral metabolism and possibly disturbed cerebral aerobic metabolism. This study argues for the avoidance of circulatory arrest whenever possible.

Blood Flow Velocity↗
PubMed1993

Absent diastolic cerebral blood flow velocity after circulatory arrest but not after low flow in infants.

It is controversial whether profound hypothermia (15 degrees C) provides adequate cerebral protection during a limited period of total circulatory arrest during pediatric cardiac surgery. In the present study, transcranial Doppler echography was used to monitor the blood flow velocity (BFV) pattern in the middle cerebral artery (MCA). The purpose of the study was to investigate the influence of a period of circulatory arrest on MCA BFV, as judged from the reperfusion flow velocity pattern. The MCA BFV was studied in 22 small children undergoing profound hypothermic cardiac operations after induction of anesthesia. Twelve of the children had a period of profound hypothermic circulatory arrest (15 to 74 minutes; arrest group). Circulation was maintained in the remaining 10 children (nonarrest group). Time-averaged MCA BFV was decreased and diastolic BFV was absent immediately after cardiopulmonary bypass in 10 of 12 children in the arrest group. In contrast, only 1 of 10 patients in the nonarrest group (p < 0.05) showed this pattern. Diastolic BFV normalized 54 to 328 minutes after the arrest in the arrest group. Circulatory arrest during profound hypothermia is followed by a period of low cerebral perfusion, whereby time-averaged MCA BFV is decreased and MCA BFV is absent during diastole. We speculate that this can be explained by an increase in intracranial pressure after brain edema.

Blood Flow Velocity↗
PubMed1989

Late results after pericardectomy for constrictive pericarditis via left thoracotomy.

Pericardectomy was performed on 28 men and 8 women (mean age 56, range 18-74 years) with diagnosis constrictive pericarditis. The etiology was unknown in 16 cases. Left anterior thoracotomy was employed in all but one case, in which median sternotomy was preferred because of extensive left pleural calcifications. There were three early and 11 late deaths. Actuarial survival at 5 and 10 years was 77% and 64%, respectively. Relief of symptoms was reported by 16 of the 33 patients (49%), who survived the postoperative period. These 16 were among the 22 survivors observed for a median of 8 (range 2-17) years postoperatively. Complete pericardectomy was achieved in all 16 asymptomatic patients, but in only nine of the 17 hospital survivors (53%), with persistent heart failure (p less than 0.01). Pericardial calcifications were significantly less common in the former than in the latter group. Lack of postoperative improvement was related to severe, nonresectable calcifications, and probably in some cases to associated fibrous epicarditis or restrictive myocardial disease. Left thoracotomy permits easier and more complete left ventricular pericardectomy, but is less safe when severe calcifications involve the right ventricle and atrium.

Adolescent↗
PubMed1989

Late results after resection of fixed subaortic stenosis.

Resection of fixed subaortic stenosis was performed on 44 patients with median age 14 (range 2-61) years. Concomitant aortic valve pathology was present in 14 (32%) cases (congenital stenosis in 2, thick fibrotic cusps in 8 and incompetent cusps in 4) and other congenital cardiovascular malformations in eight (18%). There was no perioperative mortality. Of the six late deaths, three were due to non-cardiac causes. During follow-up (median 6, range 2-21 years), six reoperations were performed for residual or recurrent obstruction and/or aortic incompetence. Aortic valve replacement was required at two primary and four second operations. Actuarial 5-year and 10-year survival rates were 89% and 76%, respectively, and rates with freedom from cardiac death endocarditis and reoperation 83% and 64%. At follow-up evaluation two patients had significant aortic regurgitation and all survivors had a systolic ejection murmur. At Doppler echocardiography in 29 patients without reoperation, the median pressure difference in the left ventricular outflow tract was 10 (range 0-55) mmHg--in three cases greater than or equal to 30 mmHg. Careful follow-up is advisable after resection of fixed subaortic stenosis, because of the risk of residual or recurrent obstruction and of significant aortic valve incompetence.

Adolescent↗
PubMed1986

Ventral herniorrhaphy aided by pneumoperitoneum.

Twenty-four patients with large abdominal incisional hernias were alternately treated with preoperative pneumoperitoneum. The insufflation was performed on an outpatient basis each day for approximately one week prior to operation. The pneumoperitoneum-treated group was spared the necessity of developing abdominal wall flaps and presented a much easier peritoneal dissection. The operative time was 50 minutes in the 12 pneumoperitoneum-treated patients compared with an average of 150 minutes in the standard repair-treated group. There were no infections in the pneumoperitoneum-treated group compared with five (42%) in the other group. The postoperative stay of the pneumoperitoneum-treated group averaged 3.5 days compared with 12.5 days for the standard repair-treated group. Pneumoperitoneum is a valuable adjunct in the repair of large ventral hernias.

Adult↗
PubMedDate not supplied

[Doppler echocardiography assessment of tricuspid valve prosthesis with normal function and with dysfunction due to obstruction].

UNLABELLED: In order to know the normal ranges of the maximum velocity and the pressure half-time between normal functioning tricuspid prostheses and malfunctioning tricuspid prostheses due to obstruction, we studied 25 patients with tricuspid prostheses (11 mechanical and 14 biological); they were divided in 2 groups: group I: 14 patients without clinical evidence of malfunction and; group II: 11 patients with malfunction due to obstruction confirmed by catheterization, surgery and/or necropsy. The peak gradient was estimated by the modified Bernoulli equation and the prosthetic valve area by the pressure halftime method. RESULTS: the mean peak velocity in group I was 147 +/- 18 cm/sec versus 165 +/- 16 cm/sec (p NS) in group II. The mean pressure half-time in group I was 124 +/- 20 msec versus 355 +/- 48 msec (p less than 0.001) in group II. CONCLUSIONS: 1. A pressure half-time greater than 200 msec is very suggestive of malfunction due to obstruction (p less than 0.001). 2. There are normo-functioning tricuspid prostheses with prolonged pressure half-time, and the values that divides these groups from those with malfunction is small: 199 and 244 msec, that is why we suggest that every patient has to have his her own echocardiographic control in the immediate postoperative period.

Adult↗
PubMedDate not supplied

[Balloon valvuloplasty in stenotic bioprosthesis].

The results of balloon valvuloplasty performed on five patients with stenotic bioprosthesis treated in the Hospital de Cardiología Centro Médico Nacional Siglo XXI, are presented. All five bioprosthesis were right sided, two in tricuspid position, one in pulmonary valve position and two in valvulated conduits from right ventricle to pulmonary artery. In all cases a pressure gradient reduction was achieved, an improvement of clinical functional class and heart failure manifestations were obtained. Mansfields balloons were used. One in two patients, and two balloons in three. We had not complications with the procedure. We conclude that balloon valvuloplasty on bioprosthesis is a safe and dependable procedure to be used in right sided bioprosthesis.

Adolescent↗
PubMedDate not supplied

[The mortality determinants in 93 cases operated on for aortic stenosis].

We report 93 cases of severe aortic stenosis. We discuss their clinical data, hemodynamic parameters, and surgical outcome. The surgical mortality and variables determining this event evaluated in groups: A (deaths) and B (survivors). Functional class (mean = 2.5 vs 2.0 p less than 0.05) was statistically as determinant for mortality as were also: transaortic gradient (group A mean = 110 +/- 37 mmHg vs group B mean = 82 +/- 31 p less than 0.005), and ejection fraction (group A mean = 55 +/- 13.7 vs group B mean = 64 +/- 14.8 p less than 0.005). Neither time of cardiopulmonary bypass nor aortic clamping were determinants for mortality. Our results are similar to those reported in other groups. Mortality rates, are determined basically by deterioration of left ventricular function, and by the severity of transaortic gradient.

Age Factors↗
PubMedDate not supplied

[Medico-surgical experience in dysfunction of heart valve prostheses. Report of 55 cases].

The medical and surgical outcome of 55 patients with prosthetic valve disfunction are reported (39 bioprosthesis and 16 mechanical). Fifty patients were operated and five had medical treatment. The group of patients with mechanical prosthesis had a functional class of 2.4 +/- .74 vs patients with bioprosthesis who had a functional class of 2.8 +/- .71. Forty eight patients (87%) had congestive heart failure, four systemic emboli and three infective endocarditis. Three cases with mechanical prosthesis in tricuspid position were subjected to thrombolysis with streptokinase and experienced clinical and echocardiographical improvement. Time elapsed from original implantation and valve disfunction was 66 +/- 56 months for mechanical prosthesis vs 108 +/- 37 months in bioprosthesis (p less than 0.01), three patients died at surgery and two during the waiting period. All deaths resulted from cardiogenic shock. All of them were previously on functional class IV.

Adult↗
PubMedDate not supplied

[Doppler echocardiography in endomyocardial fibrosis].

Twelve patients with endomyocardial fibrosis with angiographic and/or histologic corroboration were studied with Doppler echocardiography with the purpose of describing the echocardiographic features and identify the affected sites. The average age was 41 years (range 16 to 59 years), 2 men and 10 women. Three patients (25%) had isolated right ventricular involvement, one patient (8%) left ventricular, 8 patients (66%) both ventricular. Our Doppler echocardiographic findings were: right atrium enlargement (91%), right ventricle outflow dilatation (83%), paradoxical septal motion (83%), left atrial enlargement (33%), mitral and tricuspid valve prolapse (50%), pericardial effusion (41%), mitral regurgitation (75%), tricuspid regurgitation (100%), apex obliteration (50%) and a restrictive type flow pattern (50%). Doppler echocardiography is a useful method for the diagnosis of endomyocardial fibrosis, the finding of normal or small ventricles associated with apex obliteration and enlarged atria, mitral or tricuspid regurgitation and a restrictive type flow pattern are characteristics of this disease. In our population, the isolated or predominantely right ventricular involvement is the most common finding as it represented 83% of the cases.

Adolescent↗