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Biomedical subjects

J L Pomar

Publications and source records attributed to J L Pomar.

At least 19 recordsLinked to original sources
PubMed2005

In vitro evaluation of platelet reactivity toward annuloplasty devices treated with heparin coating: studies under flow conditions.

We have applied an in vitro perfusion model to explore the potential thrombogenicity of polyester annulolasty fabric used in valve repair and to investigate the possible thromboresistance characteristics conferred by a special heparin coating (Duraflotrade mark treatment). Samples of human blood from i) untreated or ii) heparin-coated extracorporeal circuits were recirculated through annular perfusion chambers containing a) untreated or b) treated annuloplasty cloth material. Perfusion experiments were performed at a shear rate of 600 s(-1) for 20 min. Platelet interaction with the material was morphometrically evaluated. In experiments performed with blood from untreated circuits and cloth material, the average cross-sectional area of platelet mass was 615 +/- 135 microm2. Treatment of cloth material with Duraflotrade mark statistically decreased the area of interacting platelets to 319 +/- 101 microm2 (*p < 0.05, n = 10). Blood samples from heparin-coated extracorporeal circuits showed a decrease of total area of platelets (308 +/- 58 microm2 vs 138 +/- 30 microm2, *p < 0.05, n = 9). The combined treatment of Duraflotrade mark in extracorporeal circuits and cloth material caused a more consistent reduction (p < 0.05). The in vitro perfusion experimental model was sensitive to evaluate the thrombogenic potential of Duraflotrade mark treatment. Our results indicate that the heparin coating of cloth material and extracorporeal circuits improves the biocompatibility of the original material and reduces the thrombogenic profile.

Aged↗
PubMed2004

Cryopreservation alters antigenicity of allografts in a porcine model of transplant vasculopathy.

UNLABELLED: The need for arterial grafts in coronary surgery to complement autologous vessels has generated interest in cryopreservation of small diameter allografts. We evaluated functional and histologic changes occurring in cryopreserved allografts 3 months after porcine femoral artery transplants. METHODS: Twenty recipient and 15 donor pigs included a control group of 16 fresh and 12 cryopreserved nonimplant arteries were used. Fresh (n=5) and cryopreserved (n=5) autografts were implanted to assess cryopreservation effects in the absence of rejection. Fresh allografts with or without treatment with cyclosporine (CsA) (n=6 of 8) and cryopreserved allografts with or without treatment with CsA (n=6 of 10) were performed to study the antigenicity of cryopreserved allografts. Arteries were stained with hematoxylin and eosin, Masson's trichrome, and orcein for morphometric analyses and immunostained to identify endothelial cells, smooth muscle cells, T lymphocytes, and macrophages. RESULTS: Among nonimplant arteries, cryopreservation reduced alpha-actin expression and increased the luminal area. All implanted autografts were patent. Cryopreserved autografts showed reduced alpha-actin expression and developed intimal hyperplasia compared to fresh autografts. Treatment with CsA improved the patency of fresh allografts from 0% to 83% (P <.01) and of cryopreserved allografts from 40% to 100% (P <.05). Cryopreserved allografts showed substantial intimal hyperplasia, and fresh allografts had more T lymphocyte infiltration in the intimal layer with aneurysmal dilatation. CONCLUSIONS: Cryopreservation reduces the deposition of inflammatory cells and prevents the thrombosis or aneurysmal lesions observed in fresh allografts. Therefore, cryopreservation modifies the antigenicity of vascular allografts.

Animals↗
PubMed2001

Aortocardiac fistulas complicating infective endocarditis.

This study sought to determine the clinical and echocardiographic features, surgical approach, and outcome of patients with infective endocarditis complicated with aortocardiac fistulas among a series of 346 consecutive cases between 1988 and 1998. Nine patients (2%) were found to have aortocardiac fistulas complicating infective endocarditis caused by highly pyogenic pathogens (4 patients had ruptured abscesses of the right sinus of Valsalva, 3 had fistulous communications from the left coronary sinus, and 1 had a fistulized abscess in the noncoronary sinus). Mortality in these patients was very high (55%), even when surgery was attempted early in the course of the disease and reconstructive procedures were implemented.

Adult↗
PubMed2001

Early clinical experience with the On-X prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: The study was designed to investigate the clinical performance of the On-X prosthetic heart valve in a multicenter experience. METHODS: Between September 1996 and September 1999, 301 patients (56% males) underwent isolated On-X valve replacement (184 isolated aortic (AVR), 117 isolated mitral (MVR)) at 11 European centers under a standardized protocol. Average age at implant was 60.2 years. Office or hospital follow up was required by the protocol; average follow up on all patients was 11 months. RESULTS: Thirty-day mortality in the study was 2.2% for AVR and 6.0% for MVR, with valve-related mortality of 0.5% for AVR. There were eight late deaths (0.7%/pt-yr AVR and 2.3%/pt-yr MVR). Two of these deaths were sudden, and thus possibly valve-related (one AVR, one MVR). Early total valve-related morbidity was 3.5% for AVR and 2.6% for MVR. In total, 13 thromboembolic events occurred; one early event in AVR resulted in death (0.5%), and one transient early event occurred in MVR (0.9%). There were 11 late events (seven AVR (1.7%/pt-yr) and four MVR (1.8%/pt-yr)), for a two-year freedom from thromboembolism of 96.6% after AVR and 97.1% after MVR. Three late bleeding events occurred, all after AVR (0.7%/pt-yr and 98.9% free at two years). Major paravalvular leaks requiring reoperation occurred on two occasions early (one AVR (0.5%), one MVR (0.8%)) and once late in MVR (0.5%/pt-yr). Late minor, untreated paravalvular leaks occurred in three AVR patients (0.7%/pt-yr) and in one MVR patient (0.5%/pt-yr). Prosthetic endocarditis occurred four times (two AVR (0.5%/pt-yr), two MVR (0.9%/pt-yr)), all within the first 12 months of surgery. Actuarial freedom from all valve-related events at two years was 88.7% for AVR and 88.1% for MVR. NYHA class was improved in 75.8% of AVR patients and 70.6% of MVR patients at two years after surgery. CONCLUSION: These early results indicate that the On-X valve provides satisfactory clinical outcome in the immediate postoperative period, and that the valve is both safe and effective.

Actuarial Analysis↗
PubMed2000

Changes in the cooling rate and medium improve the vascular function in cryopreserved porcine femoral arteries.

PURPOSE: The purpose of this study was to design an adequate technique with which to cryopreserve pig femoral arteries and to assess the influence of storage times in vascular function. METHODS: Fifty-two femoral arteries were distributed in seven groups. In group A (control), 10 arteries were studied after harvest; in groups B1 and B2, 19 arteries were suspended in RPMI 1640 plus fetal calf serum plus dimethylsulfoxide and were cryopreserved at 1 degrees C per minute or 0.3 degrees C per minute, respectively. In groups C1 to C4, 23 arteries were suspended in modified Krebs-Henseleit plus dimethylsulfoxide plus sucrose, cryopreserved at 0.7 degrees C per minute, and kept frozen for 1, 15, 60, or 180 days, respectively. After being thawed, arteries were examined for contraction and endothelial-dependent vasodilation (organ bath studies), antithrombotic properties of the endothelial layer(perfusion studies), and vessel structure (electron microscopy). RESULTS: Endothelial cells were present in both cryopreserved and control arteries. The control vessels showed a mean contraction to norepinephrine (10(-7) mol/L) of 13010 +/- 3181 mg. Arteries in groups B1 and B2 did not respond to norepinephrine. Contraction in groups C1 to C4 was as follows: C1, 5354 +/- 1222 mg; C2, 5187 +/- 2672 mg; C3, 6867 +/- 2292 mg; C4, 7000 +/- 2858 mg, which represent 50% of the control values (P <.001). Vasodilation was similar in control (99% +/- 3%) and cryopreserved arteries (C1, 90% +/- 13%; C2, 93% +/- 12%; C3, 89% +/- 15%; C4, 88% +/- 22%). Storage time did not influence vascular function. Platelet interaction was almost absent and similar in all groups. CONCLUSION: A modified cryopreservation technique preserves endothelial function independently of the storage time up to 6 months.

Acetylcholine↗
PubMed2000

Examination of hemolytic potential with the On-X(R) prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: Mechanical valves are known to produce chronic, subclinical hemolysis in most patients. Generally, haptoglobin is reduced to below normal in most patients, while lactate dehydrogenase (LDH) is increased to as much as 200% above the upper normal, sometimes resulting in anemia. The study was designed to investigate the clinical hemolysis of the On-X(R) prosthetic heart valve in a multicenter experience with a standard protocol and a single clinical laboratory. METHODS: Between September 1996 and August 1998, 248 patients underwent isolated valve replacement at 10 European centers. Blood samples were collected from these preoperatively and at 3-6 months and one year postoperatively. All samples were analyzed at a central laboratory, thus assuring poolability of the data. In total, 151 patients were tested at 3-6 months, and 62 at one year. Blood parameters measured were LDH, haptoglobin, hematocrit, total hemoglobin, red cell count and reticulocyte count. Paired analysis was used to compare preoperative baseline values with 3-6-month and one-year values. Data were analyzed with regard to both valve position and size. RESULTS: At 3-6 months and one year after surgery, average values for hematocrit, hemoglobin, red cell count and reticulocyte count were all near the center of the normal range, regardless of valve position or size. Statistically significant increases in red cell count and decreases in reticulocyte count occurred after both aortic valve replacement (AVR) and mitral valve replacement (MVR). These changes were of no clinical importance, but indicate that anemia has not occurred in these patients. At 3-6 months, haptoglobin was reduced to below normal in 86% of both AVR and MVR patients; this also occurred after one year and was statistically significant. Postoperatively, the mean LDH value in AVR was 228 U/l (91% of upper normal, 250 U/l) at 3-6 months, and 246 U/l (98% of upper normal) at one year. In MVR, these LDH values were 271 U/l (108% of upper normal) and 265 U/l (106% of upper normal). CONCLUSIONS: These results indicate that the On-X valve causes lower levels of chronic hemolysis in the immediate postoperative period and up to one year after surgery, especially when compared with reports of LDH elevations up to 200% of upper normal. Hemolytic anemia has not occurred in this patient population.

Aortic Valve↗
PubMed2000

Cardiovascular tissue banking in the non-cadaveric setting: ten-year experience of a university hospital-based bank with active organ donation program.

BACKGROUND AND AIM OF THE STUDY: Today, transplantation of cardiovascular tissues is common practice, and tissue banking has become routine. Consequently, many institutions exist which carry out high-quality tissue banking. METHODS: The Hospital Clinico of the University of Barcelona established its cardiovascular tissue bank in 1989. The bank follows international and national regulations, and functions as a non-profit-making organization. Organ and tissue donors are recruited by the Transplant Coordination unit, which works closely with the Catalonian Organ Transplant Network (OCAT) and the Spanish National Organ Transplantation Network (ONT). The hearts are removed during multi-organ donation and processed using aseptic techniques in a laminar flow hood. Hearts are only accepted from brain-dead multiorgan and non-beating-heart donors. The heart valves are dissected, decontaminated, cryopreserved in specific media and stored in liquid nitrogen at -196 degrees C under strict bacteriological and serological control. RESULTS: Between 1989 and 1999, a series of 1,005 cardiovascular donors from within Spain was identified, from which 840 hearts were processed. After evaluation, 1,099 (65.4%) valves were cryopreserved, and 1,023 (61.5%) given clearance for implantation. In total, 534 aortic, 530 pulmonary, 33 mitral and two tricuspid valves were processed; ultimately 92.8% of aortic and 93.9% of pulmonary valves were accepted for clinical implantation. The rejection rate was 39.1%. Homografts were transported to their destination in dry ice in a cryogenic container. Overall, 608 valves were implanted at our own institution and at hospitals in Barcelona and Europe. Only two cases of complaint were received from implanting surgeons. CONCLUSION: After ten years' experience, the degree of satisfaction of implanting surgeons appears to be adequate. Strict control of the entire tissue banking process has permitted the availability of high-quality homografts for clinical implantation.

Blood Vessels↗
PubMed2000

[Vancomycin and teicoplanin use as antibiotic prophylaxis in cardiac surgery: pharmacoeconomic study].

BACKGROUND: To assess the economical impact of vancomycin use versus teicoplanin use as antibiotic prophylaxis for patients undergoing cardiac surgery for valve replacement (VR) and coronary artery by-pass (CABS) procedures. PATIENTS AND METHODS: This is an ancillary cost minimization analysis of a double blinded, parallel groups, randomised clinical trial (RCT), with the main objective of comparing the safety and efficacy of these antibiotics. 500 patients were included in the study; 267 in the CABS group and 233 in the VR group. The CABS patients received 1 g vancomicin or 400 mg teicoplanin, plus 150 mg netilmicin. The VR group received a second dose of each drug after extracorporeal circulation. In order to calculate the costs we considered the direct cost of the drug, the i.v. mix and the administration costs, together with personnel and structure costs. We considered two different situations: the administration of drugs within the surgical room theatre and in the medical ward. RESULTS: The demographic data of both groups were comparable. The frequency of severe adverse drug reactions (ADR) were similar (0.4%) in both groups, as well as the post-operative infection rates (8.6%). Differences were seen in the frequencies of low severity ADRs: 20.4% in the vancomycin group and 1.6% in the teicoplanin group. When the antibiotics were administered in the surgical room, among CABS patients the costs were 8,265 pts. for the teicoplanin group and 12,005 pts. for the vancomycin group; while among VR patients, costs were respectively 11,661 pts. and 14,528 pts. Administration costs of teicoplanin and vancomycin within a medical ward setting, however, the costs were 6,740 pts. and 2,809 pts. for CABS patients, and 5,308 pts. and 10,140 pts. for VR patients, respectively. CONCLUSIONS: The costs of antibiotic prophylaxis among cardiac surgery patients heavily depends on the setting and circumstances of drug administration. The minimization cost analysis indicates that teicoplanin is the most cost-effective option if the drug is administered within the surgical area, while vancomycin is the less costly option when administered within the medical ward. However, if the second option is to be chosen, it is necessary to assure the right plasmatic drug levels of the antibiotic at the beginning of the surgical procedure.

Aged↗
PubMed1999

[The role cardiac surgery in the myocardial revascularization of patients with unstable angina in the era of interventional cardiology].

Indications for surgical myocardial revascularization in patients with unstable angina have been extended during the last years achieving similar results to those obtained in stable angina. On the other hand, percutaneous transluminal coronary angioplasty in this same subgroup of patients have achieved better results specially after the advent of intracoronary stenting. Selection of a specific technique of revascularization may be nowadays difficult and the update indications for both surgery and angioplasty are discussed.

Angina, Unstable↗
PubMed1999

Six-year experience with cryopreserved mitral homografts in the treatment of tricuspid valve endocarditis in HIV-infected drug addicts.

BACKGROUND AND AIM OF THE STUDY: In the past, valve homografts have been used in the treatment of aortic endocarditis. This report details our experience in tricuspid valve replacement using cryopreserved mitral homografts in HIV-positive drug addicts with infective endocarditis. METHODS: Five HIV-1-infected drug addicts with active uncontrollable tricuspid valve endocarditis underwent tricuspid valve replacement with a cryopreserved mitral homograft. RESULTS: There was no early mortality, and median follow up was 5 years (range: 1 to 6 years). One late mortality occurred as a result of heroin overdose. Three of the five patients developed six episodes of recurrent bacterial tricuspid endocarditis on the homograft; these were cured successfully with antibiotics. All survivors remain in NYHA functional class I. The latest transthoracic echocardiography examination showed mild, moderate or severe regurgitation in one, two and two patients, respectively. To date, neither homograft calcification nor rupture of the papillary muscle has been detected. CONCLUSIONS: This novel technique is considered to be an adequate approach to these cases of uncontrollable infectious disease. Further episodes of valvular infection can be managed medically.

Adult↗
PubMed1998

Mitroflow pericardial bioprosthesis experience in aortic valve replacement > or =60 years of age.

BACKGROUND: The Mitroflow pericardial bioprosthesis (model 11), a second-generation pericardial prosthesis, has clinical performance assessment to 10 years. The authors previously recommended the prosthesis for aortic valve replacement in patients 70 years or older. The purpose of the current assessment is to report on performance in patients 60 years or older undergoing aortic valve replacement. METHODS: This bioprosthesis was implanted in 161 patients (mean age, 69.5+/-6.3 years; range, 60 to 94 years) with aortic valve replacement from 1982 to 1992. There were 84 patients 60 to 69 years (mean, 64.5+/-3.1 years) and 77 patients 70 years or older (mean, 74.8+/-4.3 years). Of the total population, concomitant procedures were performed in 63 patients (39.1%); of these, coronary artery bypass grafting was performed in 39 (24.2%). RESULTS: The early mortality was 4.8% (4 patients) for the 60 to 69-year age group and 10.4% (8) for those 70 years or older (not significant). The late mortality was 4.4%/patient-year (27) for those 60 to 69 years and 6.9%/ patient-year (35) for those 70 years or older (not significant). The patient survival for those 60 to 69 years was 58.0%+/-6.3% and for those 70 years or older, 45.3%+/-5.9% at 10 years (p < 0.05). The valve-related mortality for those 60 to 69 years was 0.82%/patient-year (5) and for those 70 years or older, 1.58%/patient-year (8) (not significant). The reoperation rate for those 60 to 69 years was 3.29%/patient-year (20) and for those 70 years or older, 1.0%/patient-year (5) (p < 0.05). The structural valve deterioration rate for those 60 to 69 years was 3.13%/ patient-year (19) and for those 70 years or older, 1.2%/ patient-year (6) (p < 0.05). CONCLUSIONS: The Mitroflow pericardial bioprosthesis remains recommended for aortic valve replacement in patients 70 years and older.

Age Factors↗
PubMed1998

[The Institute of Cardiovascular Diseases. The redesigning project of Cardiological and Surgical Services of the Hospital Clinic of Barcelona].

Changes in health systems are determining new hospital organization forms. The patient focused hospital suppose a new radical design of hospital processes from the patient's viewpoint. This paper defines the re-engineering process of the Cardiology and Cardiovascular Surgery Services of the Hospital Clínic of Barcelona in order to develop and Institute. The change consists fundamentally in a reorganization of the direction organs, creating a staff commission and director. The chief nursing and chief management report to the director. Also, a patients admission and management unit, that manage the beds infrastructure of both services has been developed. The first year results show a reduction of the length of stay and an increase in the in-hospital and external activity.

Academies and Institutes↗
PubMed1998

[Angioplasty versus surgery in proximal stenosis of the anterior descending artery].

The points of view of the cardiac surgeon and the interventional cardiologist on their personal approach to the treatment of the significant lesions of the proximal left anterior descending coronary artery are still a matter of controversy. Two randomized studies have compared the efficacy of PTCA vs CABG in the treatment of patients with isolated proximal left anterior descending (LAD) coronary artery stenosis. After a mean follow-up of 3 years these studies concluded that the incidence of events was significantly reduced in the CABG group. However, this conclusion requires a cautious interpretation because of methodological limitations of these studies. On the other hand, a recent randomized study has shown a reduction in the restenosis rate when an intracoronary stent is electively implanted after PTCA in proximal LAD stenosis. Similarly, surgical modifications in material and in technical aspects will probably result in a reduction of the morbidity sometimes associated with surgical procedures. Presented with favourable anatomy, PTCA with elective stent implantation may be the initial option in the treatment of proximal LAD stenosis, especially if another revascularization procedure is contemplated in the future. However, CABG is preferred when the LAD lesion suggests a complicated anatomy (chronic obstructions, ostial lesions or proximal bifurcations with a significant diagonal). Depending on the particular results for both procedures in each Institution, an individual evaluation seems to be mandatory in the vast majority of patients.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Activity and morbimortality of coronary surgery in Spain].

The goal of the study is to describe the current knowledge about coronary artery by-pass surgery in Spain related to activity, institutions, and clinical outcomes. A search in the MEDLINE (1982-97) and IME (1976-97) databases and manual search in medical journals, official publications of scientific societies was performed. References whose authors or institutions in charge were located in Spain, and including data on activity, mortality and morbidity of coronary artery bypass surgery alone or in combination with other procedures. In 1995, 7,936 coronary procedures were carried out (alone or in combination) in 51 Spanish centres, representing an increase of 123% in those procedures registered and published in 1988. Hospital mortality, according to the Registry of the Spanish Society of Cardiovascular Surgery (1995), was 7.2%. Data from multicenter studies showed, allowing for variations among centres, 8.8% (1975-82) and 8.1% (1994) mortality in isolated coronary revascularization. Other studies refer to the particular experience in a centre, examining either predictive mortality factors or outcomes in specific clinical conditions. Surgical mortality has been only partially analysed in multicentre studies, although several groups refer to the incidence of their own specific complications. There are few multicentre studies assessing morbidity and mortality in coronary artery surgery and some results (quality of life, economical) have been poorly evaluated. An alternative to be considered is the creation of an advisory commission aimed at establishing health care standards and at supporting an information system on the patients characteristics, techniques applied, and results obtained in the provision of cardiological procedures that, due to their invasiveness, complexity and cost, can be considered as tertiary cardiological care.

Coronary Artery Bypass↗
PubMed1995

Large-caliber cryopreserved arterial allografts in vascular reconstructive operations: early experience.

Between October 1992 and June 1994, 16 patients (mean age, 55.6 years) underwent vascular reconstruction using cryopreserved arterial allografts. Aortoiliac aneurysms, vascular infections, and trauma accounted for the majority of case diagnoses. Twenty allografts were implanted. Two patients died in the hospital (12.5%) and 1 patient died 9 months after the operation. Early patency rate on angiography is 92.9%. Follow-up averages 8.2 months. Large-caliber cryopreserved arterial vascular allografts seem to provide satisfactory clinical results.

Adult↗