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Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 73 records · Page 4Linked to original sources
PubMed2001

[The autonomic nervous system in myocardial infarction].

The occurrence of alterations in the autonomic control of cardiovascular function has long been known. Nevertheless, only in the last 15 years with the development and utilization of techniques such as heart rate variability and baroreflex analysis, unforeseeable amounts of information have been collected. The appraisal of alterations in the autonomic control mechanisms in the acute and post-acute phase of myocardial infarction has not only confirmed the presence of an increased sympathetic and of a reduced vagal modulation in most of post-myocardial infarction patients. It has also allowed the clinically relevant identification of those patients with an increased arrhythmic and total cardiac mortality. Most the high-risk patients are indeed characterized by a marked reduction in heart rate variability that can be detected using different methodologies. For example, with time-domain analysis of heart rate variability, it has been shown that an SDNN < 70 ms identifies patients at risk. By using spectral analysis, it has been possible to realize that the loss or marked attenuation of those rhythmical components that reflect autonomic modulation is also a characteristic of the high-risk patients. A decreased responsiveness of the sinus node to autonomic inputs may also explain the reduction in baroreflex sensitivity that characterizes patients with an increased arrhythmic mortality. In conclusion, the appraisal in each patient of the extent of the alterations in the autonomic control mechanism is nowadays a critical component of the clinical assessment not only for risk stratification but also in order to guide the prescription of new pharmacological and non-pharmacological therapies.

Autonomic Nervous System↗
PubMed2000

Emergency polytetrafluoroethylene-covered stent implantation to treat coronary ruptures.

BACKGROUND: Coronary perforation is a life-threatening complication of percutaneous interventions. In the past few years, the implantation of covered stents has emerged as a strategy for treatment when the traditional conservative approach (ie, prolonged balloon inflation and reversal of anticoagulation) fails. METHODS AND RESULTS: Since May 1997 (when polytetrafluoroethylene [PTFE]-covered stents were available at our institutions), 11 of the 12 consecutive patients who had coronary ruptures that were unsuccessfully sealed with prolonged balloon inflation and reversal of anticoagulation were treated with 12 PTFE-covered stents (PTFE group). The efficacy of the PTFE-covered stent was compared with that of noncovered stents, which were used to treat 17 perforations (non-PTFE group). One patient sustained a very distal perforation that was not suitable for covered stent sealing and underwent emergency surgery. All vessel ruptures treated with PTFE-covered stent implantation were successfully sealed. The time necessary to deploy the stent was 10+/-3 minutes (range, 4 to 15 minutes). All patients but one were discharged from the hospital and had an optimal early clinical outcome. One patient underwent emergency bypass surgery and died in the intensive care unit. The occurrence of cardiac tamponade and the necessity for emergency surgery was significantly lower in the PTFE group than in the non-PTFE group. At 14+/-4 months, the 10 discharged patients had not experienced any major adverse cardiac events. CONCLUSIONS: This preliminary study supports the utility of the PTFE-covered stent for the nonsurgical treatment of vessel ruptures.

Aged↗
PubMed2000

Randomized comparison of elective stent implantation and coronary balloon angioplasty guided by online quantitative angiography and intracoronary Doppler. DESTINI Study Group (Doppler Endpoint STenting INternational Investigation).

BACKGROUND: The purpose of this study was to compare long-term outcomes of coronary stenting in all lesions (elective stenting) or only in lesions with inadequate morphological and functional results after balloon angioplasty (guided PTCA). METHODS AND RESULTS: Treatment of multivessel disease, with any lesion length and vessel size, was allowed provided that all lesions were suitable for stent implantation. Patients were randomized to elective stent implantation (n=370) or guided PTCA (n=365). An optimal PTCA result (residual diameter stenosis </=35%, coronary flow reserve measured with a Doppler guidewire >2.0, absence of threatening dissections) was achieved in 166 lesions (43%). The remaining 218 lesions underwent stent implantation (provisional stenting). Final residual diameter stenosis was lower in the elective and provisional stent groups (9.3% and 10.2%) than in the optimal PTCA group (24.8%, P:<0. 00001). On an intention-to-treat analysis, the probability of >/=1 major adverse cardiac event at 12 months was 17.8% in the elective stenting group and 18.9% in the guided PTCA group (20.1% for optimal PTCA and 18.0% for the provisional stenting subgroup, P:=NS). The incidence of repeat target lesion revascularization at 1 year was 14. 9% in the elective stent group and 15.6% in the guided PTCA group (17.6% for optimal PTCA and 14.1% for the provisional stenting subgroup, P:=NS). CONCLUSIONS: When balloon angioplasty is guided by online quantitative angiography and Doppler-derived coronary flow reserve, with provisional stenting reserved for suboptimal results, early and late clinical outcomes are comparable to those achieved by elective stenting of all patients.

Angiography↗
PubMed2000

Inhibition of restenosis with beta-emitting radiotherapy: Report of the Proliferation Reduction with Vascular Energy Trial (PREVENT).

BACKGROUND: Intracoronary gamma- and beta-radiation have reduced restenosis in animal models. In the clinical setting, the effectiveness of beta-emitters has not been studied in a broad spectrum of patients, particularly those receiving stents. METHODS AND RESULTS: A prospective, randomized, sham-controlled study of intracoronary radiotherapy with the beta-emitting (32)P source wire, using a centering catheter and automated source delivery unit, was conducted. A total of 105 patients with de novo (70%) or restenotic (30%) lesions who were treated by stenting (61%) or balloon angioplasty (39%) received 0 (control), 16, 20, or 24 Gy to a depth of 1 mm in the artery wall. Angiography at 6 months showed a target site late loss index of 11+/-36% in radiotherapy patients versus 55+/-30% in controls (P:<0.0001). A low late loss index was seen in stented and balloon-treated patients and was similar across the 16, 20, and 24 Gy radiotherapy groups. Restenosis (>/=50%) rates were significantly lower in radiotherapy patients at the target site (8% versus 39%; P:=0.012) and at target site plus adjacent segments (22% versus 50%; P:=0.018). Target lesion revascularization was needed in 5 radiotherapy patients (6%) and 6 controls (24%; P:<0.05). Stenosis adjacent to the target site and late thrombotic events reduced the overall clinical benefit of radiotherapy. CONCLUSIONS: beta-radiotherapy with a centered (32)P source is safe and highly effective in inhibiting restenosis at the target site after stent or balloon angioplasty. However, minimizing edge narrowing and late thrombotic events must be accomplished to maximize the clinical benefit of this modality.

Angioplasty, Balloon, Coronary↗
PubMed2000

Heparin-coated Wiktor stents in human coronary arteries (MENTOR trial). MENTOR Trial Investigators.

The purpose of this study was to determine the feasibility, safety, and efficacy of elective stenting with heparin-coated Wiktor stents in patients with coronary artery disease. In experimental studies, heparin coating has been shown to prevent subacute thrombosis and restenosis. Recently, a new method of heparin coating was developed, resulting in a more stable and predictable heparin layer on stent devices. This trial constitutes the first in-human use of this coating procedure, applied on the well-known Wiktor stent device. Heparin-coated Wiktor stent implantation was performed in 132 consecutive patients (132 lesions) in a multicenter international trial from September 1996 to February 1997. Forty-three percent of patients had unstable angina, 33% had previous myocardial infarction, and 10% had diabetes mellitus. Patients were followed for 12 months for occurrence of major adverse cardiovascular events, and 96% of the eligible patients underwent quantitative angiographic control at 6 months. Stent deployment was successful in 95.5% of lesions. Minimal lumen diameter increased by 1.67 +/- 0.48 mm (from 1.02 +/- 0.38 mm before to 2.69 +/- 0.37 mm after the stent implantation). Mean percent diameter stenosis decreased from 67.4 +/- 11.3% before to 18.9 +/- 7.7% after the intervention. A successful intervention (<50% diameter stenosis and no major adverse cardiac events within 30 days) occurred in 97% of the patients. The subacute thrombosis rate was 0.8%, which compares favorably with historical controls of this stent, and a low incidence of postprocedural increase in creatine kinase-MB was noted. At 6 months, event-free survival was 85% and angiographic restenosis rate was 22% with late loss of 0.78 +/- 0.69 mm and a loss index of 0.48 +/- 0.44. Heparin-coated Wiktor stents appeared to be an efficacious device to treat Benestent-like lesions, yielding angiographic and clinical results comparable to a heparin-coated Palmaz-Schatz stent. Despite its use in more complex lesions, the incidence of subacute thrombosis appeared to be lower than historical controls with a similar noncoated stent.

Angioplasty, Balloon, Coronary↗
PubMed2000

Polytetrafluoroethylene-covered stent for the treatment of narrowings in aorticocoronary saphenous vein grafts.

We compared the outcome of patients with saphenous graft disease treated with polytetrafluoroethylene (PTFE)-covered stents or noncovered stents. Angiographic success was similar; non-Q-wave myocardial infarction was lower in the PTFE group (p = 0.06) and long-term major cardiac events and restenosis rate were similar in the 2 groups. Implantation of PTFE-covered stent in vein graft disease seems to reduce the occurrence of distal embolization.

Aged↗
PubMed2000

Development of an immunoenzymatic assay for the detection of human antibodies against Trypanosoma cruzi calreticulin, an immunodominant antigen.

We have developed an indirect immunoenzymatic assay (ELISA) for the detection of human antibodies against calreticulin (formerly known as Tc45), a dimorphic Trypanosoma cruzi antigen, described in our laboratory. PVC microtitration plates were sensitized with the monoclonal anti-calreticulin antibody (MoAb) and reacted with calreticulin present in a partially purified preparation. The presence of anti-T. cruzi calreticulin IgG in sera from infected individuals was tested. The data generated with this assay were validated by correlation, in a regression analysis, with those obtained by an indirect immunoradiometric assay (IRMA). From the 12 seropositive sera (as defined by a commercial test), eight came out positive and four negative in both assays. The 12 human sera were also analyzed in direct immunometric assays (ELISA and IRMA), where the solid phase was sensitized with a whole parasite extract. The direct ELISA and IRMA correlated positively (P<0.01). Further validation of this ELISA was achieved with an indirect immunofluorescense assay. The high degree of significance obtained when the indirect IRMA and ELISA systems were compared, indicated that the relatively small sample number used (12) was statistically satisfactory for the purposes of this investigation. Thus, the IRMA can be replaced by the ELISA, with advantages mainly derived from the cumbersome manipulation of radioactive wastes. The MoAb used as an antigen capture agent in the ELISA proposed here, recognizes a homologous protein in Trypanosoma rangeli, suggesting that individuals infected with this parasite might have crossreactive antibodies. However, the system retains its diagnostic interest, given the facts that the MoAb does not recognize a homologous protein in Leishmania mexicana, Leishmania donovani, or Crithidia fasciculata.

Animals↗
PubMed2000

Edge restenosis after implantation of high activity (32)P radioactive beta-emitting stents.

BACKGROUND: A high restenosis rate has been reported at the edges ("edge restenosis") of (32)P radioactive stents with an initial activity level of 3 to 12 microCi. This edge effect might be due to balloon injury and to a low dose of radiation at the stent margins. The aim of this study was to evaluate whether the implantation of (32)P radioactive stents with a higher activity level (12 to 21 microCi) combined with a nonaggressive stent implantation strategy could solve the problem of edge restenosis. METHODS AND RESULTS: We compared the results of lesions treated with single radioactive BX stents with an activity of 12 to 21 microCi (group 2, n = 54 lesions) with the results of lesions treated by single radioactive BX stents with an initial activity level of 3 to 12 microCi (group 1, n = 42 lesions). There were no procedural events. At the 6-month follow-up, no myocardial infarctions, deaths, or stent thromboses had occurred. Intrastent binary restenosis was 0% in group 1 versus 4% in group 2 (n = 2, both at the ostium of the right coronary artery, P = NS). Intrastent neointimal hyperplasia was significantly lower in group 2 than in group 1. The intralesion (intrastent plus peri-stent) restenosis rate was 38% in group 1 versus 30% in group 2 (P = NS). Conclusions-Single (32)P radioactive stents with an initial activity level of 12 to 21 microCi reduced intrastent neointimal hyperplasia compared with stents of 3 to 12 microCi, but they did not solve the problem of edge restenosis, even if a nonaggressive stent implantation strategy was used.

Angioplasty, Balloon, Coronary↗
PubMed2000

Immediate and long-term results of "T" stenting for bifurcation coronary lesions.

The technique of "T" stenting, which incorporates wiring both the branches of a bifurcation lesion, dilating a balloon in the main branch during stent deployment in the side branch followed by deployment of stent in the main branch, provides excellent immediate results in terms of technical and procedural success. However, further innovations are mandated to optimize the long-term outcome, which with a restenosis rate of 63%, can be described as not encouraging.

Angioplasty, Balloon, Coronary↗
PubMed2000

Procedural costs of digital vs. analog archiving of diagnostic cardiac catheterizations.

The use of digital technology in the cardiac catheterization laboratory is expanding at a rapid pace. The cost-effectiveness of this new technology is yet to be proven. The aims of this study were to determine the direct cost differences of digital versus analog media (CDs) for the storage of diagnostic cardiac catheterizations and to explore the factors influencing these differences. Procedural costs of all diagnostic angiograms (n = 109), from three physicians, performed in an analog catheterization laboratory (room A) and a digital catheterization laboratory (room C) were compared during a 9-month period. The mean procedural cost was higher in room A than in room C ($1,102 vs. $1,087, P < 0.001). This cost difference was eliminated when recording media costs were excluded from analysis ($1,079 vs. $1,080, P = 0.931). Therefore, we conclude there is a procedural cost savings in a cardiac catheterization room that uses digital CDs versus cineangiogram film as the archival media. Cathet. Cardiovasc. Intervent. 49:246-250, 2000.

Cardiac Catheterization↗
PubMed2000

Coronary stenting versus balloon angioplasty in small coronary artery with complex lesions.

The impact of stenting on small vessels (< 3.0 mm) with complex lesions (B2-C) is still controversial. Restenosis rate in this population is high (> 40%). We compared early and late outcome of patients with complex coronary lesions in small vessel treated with traditional coronary angioplasty (angioplasty group) and with elective stent implantation (stent group). Angioplasty group (n = 97) and stent group (n = 112) were comparable for all clinical and angiographic characteristics. All patients in the two groups had clinical and angiographic follow-up. Major adverse cardiac events (MACE) and restenosis rate were evaluated. No patients in the two groups experienced in-hospital death or bypass surgery. Myocardial infarction occurred in four patients in the angioplasty group and in seven patients in the stent group (P = 0.36). No patients in either the angioplasty or the stent group had acute stent thrombosis, whereas subacute stent thrombosis occurred in only one patients of the stent group (0.9%). Long-term MACEs (20 +/- 4 month) were not different in the two groups (angioplasty group 39% vs. stent group 44%, P = 0.35). Target lesion revascularization rate was 33% in the angioplasty group and 34% in the stent group (P = 0.50). Restenosis rate was not statistically different in the two groups (stent group 41% vs. angioplasty group 38%, P = 0.41). In conclusion, compared to balloon angioplasty, elective stent implantation in small vessels with complex lesions does not improve early and late outcome. Cathet. Cardiovasc. Intervent. 50:390-397, 2000.

Angioplasty, Balloon, Coronary↗
PubMed2000

Cutting balloon angioplasty for the treatment of in-stent restenosis.

The results using the Cutting Balloon for the treatment of in-stent restenosis may be superior to those of conventional percutaneous transluminal coronary angioplasty (PTCA) or even the combination of PTCA preceded by rotational atherectomy. The reasons for these possible differences are not yet well defined. The case we report suggests that the Cutting Balloon achieves a better final result than conventional PTCA, by making the tissue more amenable to being pushed outward through the stent struts.

Angioplasty, Balloon, Coronary↗
PubMed2000

Left internal mammary artery graft perforation repair using polytetrafluoroethylene-covered stents.

The increase in the use of the left internal mammary artery (LIMA) as graft of choice to the left anterior descending coronary artery for conventional and minimally invasive coronary artery bypass surgery has led to an increased incidence of LIMA pathologic lesions early after surgery. The lesion, commonly located in the body of the LIMA graft, is usually caused by mechanical injury during harvesting of the vessel. In this context, percutaneous intervention with stent implantation can be complicated by vessel rupture, which usually requires emergency surgical repair. We describe two cases of stent implantation in newly placed LIMA grafts complicated by vessel rupture, which were successfully repaired using polytetrafluoroethylene-covered stents.

Aged↗