Direct Angioplasty Research Articles

Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting.

Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.

Reperfusion therapy for acute myocardial infarction. Which strategy for which patient?

Several modes of reperfusion therapy for evolving myocardial infarction (MI) have been developed, which differ in terms of effectiveness, complexity and costs. Reperfusion resources are often restricted by budgetary or logistical circumstances. To arrive at an equitable distribution of treatment options, physicians should therefore consider which treatment to apply in which patient. Two major questions which arise in this respect are discussed here: what is the treatment effect in an individual patients, and what is an equitable resource allocation? Currently, the most relevant treatment options are: streptokinase (1.5MU over 1h), reteplase (2 boluses of 10MU), alteplase (tissue plasminogen activator; t-PA) [100mg over 1.5 hours] and immediate angioplasty. In combination with aspirin, streptokinase leads to an almost 40% mortality reduction at 1 month compared with placebo [from 13.2 to 8.0%; Second International Study of Infarct Survival (ISIS-2) trial]. The Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-1) study demonstrated a further mortality reduction by early combination therapy of aspirin, intravenous heparin and alteplase vs aspirin, heparin (either intravenous or subcutaneous) plus streptokinase (from 7.3 to 6.3%). The clinical effects of reteplase fall somewhere between those of streptokinase and alteplase. Combined analysis of the angioplasty trials suggests that angioplasty is superior to thrombolysis, especially in patients with a high cerebral bleeding risk. The noticed gradient of efficacy runs parallel to a gradient of costs and complexity: streptokinase is the least costly treatment option while direct angioplasty is the most expensive and complex. Subgroup analyses indicate that there are neither apparent deviations in the relative effect of reperfusion therapy as compared to control treatment, nor in the additional effect of more intensive therapy (alteplase) upon 'standard' therapy (streptokinase). Consequently, the absolute number of deaths avoided by reperfusion therapy appears to be greatest in those groups with a high mortality risk without therapy. There is one major exception: in patients treated early after symptom onset a much greater relative mortality reduction is observed than in those treated later. Owing to the higher mortality risk, the life expectancy of a patient with MI is shorter than that of an 'average' person of the same community and the same age. Since mortality reduction of reperfusion therapy is maintained at long term follow-up, part of this potential loss can be regained. This 're-gain of lost years' is judged to be the ultimate treatment effect in an individual patient. An equitable treatment allocation should be such that patients who will benefit most will receive the most effective therapy, while patients with similar expected benefit will be offered the same mode of therapy. The conclusion is that treatment guidelines or protocols can be very useful in clinical practice, especially if rapid decision making is of vital importance.

Pre-hospital treatment with abciximab in acute myocardial infarction with direct percutaneous transluminal coronary angioplasty

Pre-hospital treatment with abciximab in acute myocardial infarction with direct percutaneous transluminal coronary angioplasty

Coronary vasoreactivity to ergonovine after angioplasty: difference between the infarct-related coronary artery and the noninfarct-related coronary artery

Background: The vasoreactivity after direct percutaneous transluminal coronary angioplasty (PTCA) in patients with previous myocardial infarction remains unknown. We examined the constrictor responce to ergonovine of the infarct-related coronary artery in comparison with that of noninfarct-related coronary artery after angioplasty. Methods: Ergonovine was administered intravenously to 17 patients with previous myocardial infarction (group I) and to 21 patients with stable angina (group II) 1 year after PTCA. The effects of ergonovine on lumen diameter were analysed quantitatively at the PTCA segment, nonPTCA segment (proximal to the PTCA segment), and nonPTCA artery. Results: The ergonovine-induced decrease in minimal lumen diameter at the PTCA segment was significant in group I (decrease from 2.12 ± 0.56 to 1.39 ± 0.74 mm, P < 0.01), but not in group II (decrease from 1.60 ± 0.35 to 1.43 ± 0.33 mm, NS). Patients in group I showed a constrictor response at the nonPTCA artery (decrease in diameter from 2.54 ± 0.90 to 1.94 ± 0.77 mm, P < 0.01), and a tendency to constrict at the nonPTCA segment (2.56 ± 0.67 to 2.11 ± 0.66 mm, P = 0.06), whereas those in group II showed no significant constrictor response to ergonovine at any of the three segments examined. The changes in diameter at the three segments in patients in group I were significantly greater than those in group II (all P < 0.01). Subtotal coronary spasm at the PTCA segment was provoked only in three patients in group I (18%). Conclusions: The constrictor response to ergonovine of the infarct-related coronary artery was enhanced compared with that of the noninfarct-related coronary artery. This difference in coronary vasoreactivity at the angioplasty segment may be due to previous hypersensitivity of the smooth muscle. Coronary Artery Dis 9:105-111 1988 Lippincott-Raven Publishers.

Use of anti-GP IIb-IIIa in acute thrombosis after intracoronary stent implantation.

Acute occlusion of coronary stents still occurs in 0.5-2% of patients. The usefulness of GP IIb-IIIa receptor inhibitors has never been evaluated in this indication. After 1,454 stent implantations, acute occlusion occurred in 16 patients. Direct percutaneous transluminal coronary angioplasty (PTCA) was immediately performed. In eight patients, no recurrent thrombosis occurred during the 15 min following PTCA, and abciximab infusion was started after this period. In six patients, immediate recurrent thrombosis occurred in the stent. In these cases, an intravenous bolus of abciximab followed by a new inflation at low pressure was performed. Fifteen min after the bolus, stable TIMI 3 flow was restored in all six cases, and no thrombus or haziness remained. In two patients, a TIMI 0 flow persisted despite PTCA and the use of a bolus of abciximab. No recurrent ischemic symptoms were observed before hospital discharge. Abciximab in combination with balloon angioplasty can be used safely to control acute thrombosis after stent deployment.

Intraoperative Angiography in Minimally Invasive Direct Coronary Artery Bypass Grafting

Intraoperative angiography in minimally invasive direct coronary artery bypass grafting without cardiopulmonary bypass and in hybrid procedures is reported. Twelve procedures were performed in a specially designed surgical-radiologic suite with a cross-disciplinary organization. In 2 patients the anastomosis was successfully revised on the basis of angiographic findings. In 4 of the 12 patients anastomosis of the left internal mammary artery to the left anterior descending coronary artery performed as a minimally invasive direct coronary artery bypass grafting procedure was combined with percutaneous transluminal coronary angioplasty of lesions in other coronary vessels in the same session. Intraoperative angiography allows a reliable diagnosis of an anastomosis or graft failure and prompt and reliable correction, and it allows the combination of minimally invasive direct coronary artery bypass grafting and angioplasty in one session.

Staged minimally invasive direct coronary artery bypass and percutaneous angioplasty for multivessel coronary artery disease

Objective: Minimally invasive direct coronary artery bypass (MIDCAB) using the left internal mammary artery (IMA) to the left anterior descending (LAD) coronary artery can be performed with low operative risk. MIDCAB can be combined with percutaneous transluminal coronary angioplasty (PTCA) to treat patients with multivessel disease. We report here our experience with staged MIDCAB and PTCA in the management of a selected group of patients. Methods and results: 11 patients (9 males, mean age 64.6±8.7 years) with multivessel coronary artery disease received left IMA grafts to the LAD using the MIDCAB approach. There were no postoperative morbidity or mortality. All patients were extubated within 4 h of leaving the operating room with a mean ITU stay of 12.8 h. All patients but two underwent coronary angioplasty during the same hospital admission, 3.8±1.3 days after the MIDCAB procedure. Angiography confirmed IMA grafts patency in all patients, and complete revasularisation by PTCA of other coronary arteries was possible in all patients but one. Mean hospital stay was 5.9 days, and all patients remain free of angina at a mean follow-up period of 11.4 months. Conclusions: Staged MIDCAB and angioplasty is an experimental approach for the management of selected patients with multi-vessel coronary artery disease. Further experience is needed to clarify patient selection and the long-term outcome of this approach.

Recovery of Myocardial Perfusion in Acute Myocardial Infarction After Successful Balloon Angioplasty and Stent Placement in the Infarct-Related Coronary Artery

Objectives. This study sought to investigate changes in myocardial perfusion after direct percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (MI).Background. After initially successful recanalization of the infarct-related artery, coronary perfusion may deteriorate as a result of reocclusion, distal embolization of platelet aggregates formed at the dilated plaque or microvascular reperfusion injury. This change could offset the benefit from early intervention.Methods. The study included 19 patients in whom the infarct-related artery was successfully recanalized by PTCA with Palmaz-Schatz stent placement within 24 h after the onset of pain. Basal and papaverine-induced coronary blood flow were assessed by Doppler flow velocity measurements and quantitative coronary angiography. In addition, basal and adenosine-induced myocardial blood flow were measured by nitrogen-13 ammonia positron emission tomography (PET).Results. Immediately after completion of the intervention, the average coronary flow reserve (CR) in the recanalized vessel was 1.56 ± 0.51; it increased to 2.04 ± 0.65 at 1 h (p = 0.013) and to 2.66 ± 0.72 at 2 weeks after reperfusion (p = 0.008, n = 16). PET studies in 12 patients revealed that perfusion defect size and CR in the infarct region (2.19 ± 0.89 vs. 2.33 ± 0.86) did not change significantly between day 2 after recanalization and 2 weeks. However, we found significant (p < 0.03) increases in basal (by 26%) and adenosine-induced (by 40%) blood flow in the infarct region.Conclusions. Despite the persistence of a perfusion defect after successful recanalization of the occluded artery in acute MI, CR of the infarct region improves in most patients within 1 h and further improves within 2 weeks.

Reperfusion Therapy for Acute Vertebrobasilar Occlusion

We reviewed retrospectively our experience in treating 10 patients with acute vertebrobasilar occlusion. Nine patients were treated with interventional reperfusion therapy and the remaining one patient with top of the basilar embolism was treated conservatively because of deep coma and decerebrate rigidity with severely reduced cerebral blood flow (CBF) in the brain stem. Among 9 patients with reperfusion therapy, 8 patients underwent intra-arterial thrombolytic therapy and the other one patient had direct percutaneous transluminal angioplasty (PTA). Eight patients had basilar artery occlusion, 1 patient treated with direct PTA had bilateral intracranial vertebral artery occlusion and the other patient had left posterior cerebral artery occlusion presumably preceding top of the basilar embolism. In 4 of 10 patients, residual CBF was evaluated by single photon emission computed tomograpy (SPECT). Successful recanalization with clinical improvement was achieved in 6 of 9 patients (66.7%) treated with reperfusion therapy. In patients with progression or fluctuation of incomplete brain stem syndrome, SPECT revealed preserved residual CBF and successful recanalization with clinical improvement was achieved by interventional reperfusion therapy. On the other hand, in patients with persistent deep coma and decerebrate rigidity, SPECT revealed marked reduction of residual CBF in the brain stem and recanalization could not improve clinical outcome. Preoperative SPECT may be useful to make a decision whether rep er fusion therapy should be performed or not in case of vertebrobasilar occlusion.

Noninvasive prediction of residual blood flow within the risk area during acute myocardial infarction: A multicenter validation study of patients undergoing direct coronary angioplasty

Background In a previous study from a single center, radionuclide measures of collateral flow with technetium 99m sestamibi have been shown to be significantly associated with angiographic residual (antegrade and collateral) flow and independent predictors of final infarct size in acute myocardial infarction. This study examined whether the previously described radionuclide measures of blood flow to the infarct zone were reproducible with different laboratories and imaging systems. Methods and Results Residual flow to the infarct zone was assessed by both invasive and noninvasive methods in 77 patients with first-time myocardial infarction (32 anterior, 45 nonanterior). All patients underwent acute coronary angiography before any intervention within 8 hours of the onset of chest pain (4.0 ± 1.5 hours; range 1.2 to 7.9 hours). 99m Tc sestamibi was injected intravenously before reperfusion therapy, and tomographic imaging was performed 1 to 6 hours after injection. A central core laboratory processed the acquired images from three centers, each with a unique camera and computer system. Three previously published methods based on the severity of the acute perfusion defect were used to measure residual flow to the infarct zone (nadir, severity index, area). Antegrade (Thrombolysis in Myocardial Infarction flow) and collateral flow before direct angioplasty were blindly graded on a four-point scale (0 to 3) from the acute angiogram. The simple sum of the two grades was defined as the angiographic flow index, representing residual flow to the jeopardized zone. All three noninvasive measures of residual flow were highly associated with the angiographic flow index in a linear fashion: severity index ( p = 0.0006), area ( p = 0.003), and nadir (minimum/maximum counts; p = 0.004). This association was independent of the laboratory where the data were acquired. Conclusions Despite different laboratories and camera systems, radionuclide measures of residual flow were highly associated with the angiographic flow index before reperfusion therapy. These results suggest that these measures are applicable on a broader scale for the noninvasive determination of collateral and antegrade flow in acute myocardial infarction. (Am Heart J 1997;134:639-46.)

Vitronectin receptor (alpha(v)beta3) mediates platelet adhesion to the luminal aspect of endothelial cells: implications for reperfusion in acute myocardial infarction.

Platelet interaction with endothelium plays an important role in the pathophysiology of coronary microcirculation. We assessed the role of the vitronectin receptor (integrin alpha(v)beta3) in platelet/endothelium adhesion. We investigated the effect on platelet/endothelium adhesion of plasma obtained from patients with acute myocardial infarction during reperfusion (before and 8, 24, 48, and 72 hours and 5 to 7 days after direct angioplasty) and with pretreatment with alpha-thrombin (2 U/mL) and recombinant human interleukin-1beta. Platelet/endothelium adhesion was significantly enhanced by approximately 20% after pretreatment of endothelium with patient plasma for 4 hours (P<.05) compared with endothelium treated with pooled control plasma. Plasma-induced platelet/endothelium adhesion was, in part, RGD peptide dependent. Pretreatment of endothelial cells with alpha-thrombin or recombinant human interleukin-1beta enhanced platelet/endothelium adhesion and surface expression of alpha(v)beta3 on the luminal aspect of endothelium (P<.05). The adhesion of platelets, isolated platelet microparticles, and Chinese hamster ovary cells bearing human recombinant alpha(IIb)beta3 (platelet glycoprotein IIb-IIIa) to activated endothelial cells was inhibited by antiadhesive peptides GRGDSP and c(RGDfV) and monoclonal antibodies 4F10, LM609, and 7E3. The expression of vitronectin receptor exposed on the luminal aspect of activated endothelium is enhanced and mediates platelet/endothelium adhesion. Vitronectin receptor-mediated platelet attachment to activated endothelium during reperfusion may contribute to reperfusion injury and could be a target for antiadhesive therapy.

Rapid Reduction of ST-Segment Elevation After Successful Direct Angioplasty in Acute Myocardial Infarction

The aim of this study was to evaluate whether assessment of ST-segment changes in the 12-lead electrocardiogram from admission to 30 minutes after successful direct coronary angioplasty can predict myocardial damage and functional outcome in patients with acute myocardial infarction (AMI). Of 158 consecutive patients, 117 (92 men, aged 61 ± 11 years) were prospectively classified into 2 groups: group 1, <50% reduction in ST-segment elevation in a single selected lead (42 patients); group 2, ≥50% reduction in ST-segment elevation (75 patients). Baseline characteristics were similar except for anterior wall AMI and Killip class >2, which were more prevalent in group 1. Peak creatine kinase was significantly higher in group 1 (3,690 ± 2,809 vs 2,592 ± 1,960 U/L; p = 0.018). One-month echocardiograms were obtained in 102 patients (87%). Infarct zone wall motion score index decreased in both groups, but this reduction was higher in group 2 (p <0.001). Functional recovery (>0.22 decrease in infarct zone wall motion score index) was observed in 34% of group 1 and in 78% of group 2 patients (p <0.001). One-month left ventricular ejection fraction was higher in group 2 (p <0.001). At multivariate analysis, reduction of ST-segment elevation was the only independent predictor of functional recovery (p <0.001). In conclusion, ST-segment analysis provides rapid and inexpensive information allowing identification of patients who are likely to benefit the most from myocardial reperfusion as early as 30 minutes after the last balloon inflation.

Direct percutaneous transluminal angioplasty for acute embolic middle cerebral artery occlusion: Report of two cases

Direct percutaneous transluminal angioplasty for acute embolic middle cerebral artery occlusion: Report of two cases

Initial experience with long coronary stents: The changing practice of coronary angioplasty

The initial experience with the use of long coronary stents (>30 mm in length) was analyzed retrospectively. Sixty-seven stents were deployed in 58 narrowings in 57 patients (34 AVE Microstents, 16 Nir stents, four Gianturco-Roubin II stents, and 13 Wallstents). Stents were implanted in 22 patients with unstable angina, 34 patients with stable angina, and one patient during direct angioplasty for acute myocardial infarction. Eighteen additional short stents were implanted to cover the entire length of the lesions so that an average of one and a half stents were deployed per patient. The length of the narrowings before stenting was 40 ± 20 mm and the length of the stented segments was 45 ± 20 mm. Stents were deployed for “bailout” in 23 narrowings, to improve suboptimal results of balloon angioplasty in 18 narrowings, and electively in 17 narrowings. Twenty of the 67 long stents were deployed in saphenous vein grafts. The success rate of stent implantation was 100%. One patient had a rupture of a saphenous vein graft after deployment of two long stents, with tamponade treated by emergency surgery. One patient had chest pain 18 hours after stent deployment; by the time he arrived at the catheterization laboratory the pain had subsided and the angiogram revealed a patent artery with normal flow. There were no other major complications during the hospital course and 1-month follow-up. We conclude that long coronary stents can be deployed successfully in native coronary arteries and vein grafts. They are useful for elective implantation and extremely helpful in bailout situations. The immediate results are excellent, but long-term outcome is awaited. (Am Heart J 1997;134:355-61.)

Prognostic Value of Slow Resolution of ST-Segment Elevation Following Successful Direct Percutaneous Transluminal Coronary Angioplasty for Recovery of Left Ventricular Function

Our objective was to investigate the significance of the slow resolution of ST-segment elevation following a successful direct percutaneous transluminal coronary angioplasty (PTCA). ST-segment elevations were calculated from electrocardiograms recorded before PTCA and 1 hour after reperfusion. Forty-nine patients experiencing their first anterior acute myocardial infarction and who had undergone direct PTCA were classified into 3 groups: 17 patients with rapid ST resolution (group I), 23 patients with persistent ST elevation (group II), and 9 patients with ST reelevation (group III). Left ventricular function was evaluated by using single-plane cineventriculography performed in the acute stage, at discharge, and 4 months later. Peak creatine kinase activity was significantly increased: group III (4,046 ± 634 IU), group II (3,336 ± 772 IU), and group I (2,410 ± 994 IU); p <0.05. Ejection fraction and regional wall motion in the acute stage were identical in each group. However, they were significantly higher in group I (67 ± 6%, −1.01 ± 0.30), followed by group II (56 ± 6%, −1.90 ± 0.41) and group III (38 ± 7%, −2.79 ± 0.46); p <0.01 4 months later. Multiple regression analysis revealed that the ST resolution was the only significant variable that indicated the recovery of regional wall motion. A good linear correlation was documented between the ST resolution and the recovery of regional wall motion. We concluded that a slow ST resolution after successful direct PTCA is a negative predictor of recovery of left ventricular function, especially when ST reelevation is evident.

Direct Percutaneous Transluminal Angioplasty for Acute Embolic Middle Cerebral Artery Occlusion: Report of Two Cases

Direct Percutaneous Transluminal Angioplasty for Acute Embolic Middle Cerebral Artery Occlusion: Report of Two Cases

Myocardial viability assessed by Dobutamine echocardiography in acute myocardial infarction after successful primary coronary angioplasty

Dobutamine echocardiography (5 and 10 μg/kg/ min) was performed in 40 patients 4 ± 1 days after acute myocardial infarction reperfused by primary coronary angioplasty. The left ventricle was divided into 11 segments. Reversible myocardial dysfunction was indicated by a decrease in at least 2 grades in the total segmental score. Follow-up echocardiography was performed 2 months later. Contractile reserve was documented in 18 patients with dobutamine echocardiography (45%). Sensitivity, specificity, positive, and negative predictive value of dobutamine echocardiography in predicting improvement in contractile function at follow-up were 82%, 83%, 78%, and 86%, respectively. Negative predictive value was high in all dyssynergic segments (86%). Positive predictive value was higher in hypokinetic than in akinetic segments (73% vs 21%; p < 0.05). Recovery of wall motion at follow-up was statistically associated with higher left ventricular ejection fraction (p < 0.04), collateral blood flow before reperfusion (p = 0.007), and dobutamine responsiveness (p = 0.0001), and was more frequently observed in hypokinetic than in akinetic segments (p < 0.05). Thus, low-dose dobutamine echocardiography accurately predicts the extent of irreversibly damaged myocardium early after successful direct coronary angioplasty in acute myocardial infarction.

Thrombolytic Therapy for Eligible Elderly Patients With Acute Myocardial Infarction

To determine the correlates of thrombolytic therapy use in a population-based sample of elderly patients hospitalized with acute myocardial infarction who were eligible for the therapy on presentation. Retrospective cohort study using data from medical charts and administrative files. All acute care, nongovernmental hospitals in Connecticut. A cohort of 3093 patients aged 65 years and older with a discharge diagnosis of acute myocardial infarction covered by Medicare from May 1992 to May 1993. Among the 753 patients with ST-segment elevation of 1 mm or more in at least 2 contiguous leads, left bundle branch block not known to be old, and no absolute contraindications to thrombolytic therapy who were not referred for direct angioplasty or bypass surgery, 419 patients (56%) did not receive thrombolytic therapy. The strongest predictors of not receiving thrombolytic therapy included advanced age, absence of chest pain, presentation more than 6 hours after the onset of symptoms, left bundle branch block, total ST-segment elevation of 6 mm or less, presence of Q waves, ST-segment elevation in only 2 leads, and altered mental status. Physicians documented why they did not administer thrombolytic therapy in 19% of the charts. Delay in presentation and increased age were the most common reasons cited. Among the subset of 261 patients who presented with chest pain and within 6 hours of symptoms, 197 (75%) received thrombolytic therapy. Many eligible and ideal patients for thrombolytic therapy are not treated. Physicians are less likely to use thrombolytic therapy in eligible patients with characteristics associated with an increased risk of bleeding, lower-risk infarction, less certain diagnosis, less certain efficacy, or altered mental status. These findings suggest that the lack of treatment represents a clinical judgment rather than an inadvertent omission. In some cases, such as the lower use of thrombolytic therapy with older age, these judgments are not consistent with the published literature and may represent opportunities to improve care.

Adenosine for Myocardial Protection in Acute Myocardial Infarction

Although reperfusion therapy for acute myocardial infarction is known to reduce infarct size, improve left ventricular function, and reduce mortality, the full potential benefit may be limited by acceleration of damage resulting from reperfusion, or “reperfusion injury.” Evidence of a variety of mechanisms of reperfusion injury has led to a wide range of proposed therapeutic interventions, including agents to prevent oxygen free radical damage, inhibit white blood cell function, reduce calcium influx, improve microvascular blood flow, inhibit sympathetic stimulation, and improve energy stores. A multitude of agents have been shown to limit infarct size in animals when administered before or during reperfusion. Unfortunately, most have been disappointing when tested clinically. Adenosine, a theoretically attractive agent for preventing reperfusion injury, has shown promise in small, clinical studies, and appears to be an endogenous substance involved in the protective effect of ischemic preconditioning. When studied in the setting of angioplasty for acute myocardial infarction, adenosine was associated with small infarct size and improved coronary flow. As myocardial preservation with reperfusion during bypass surgery shares pathophysiologic characteristics with the reperfused myocardium in acute infarction, early results of adenosine during bypass surgery presented at this symposium support the concept that adenosine may be beneficial. Two ongoing Phase II trials of adenosine in acute myocardial infarction—one with thrombolysis and one with direct angioplasty—will provide important information about the potential benefits of adenosine in the context of reperfusion.

Early detection of successful coronary reperfusion based on serum concentration of human heart-type cytoplasmic fatty acid-binding protein

Both human heart-type cytoplasmic fatty acid-binding protein (H-FABPc) and myoglobin are low molecular weight proteins that are abundant in the cytoplasm of myocardial cells. Unlike myoglobin, H-FABPc content in the skeletal muscle is less than in cardiac muscle. To investigate the usefulness of the serum concentration of H-FABPc in the early detection of successful coronary reperfusion, we measured serum concentrations of H-FABPc and myoglobin in 45 patients with acute myocardial infarction treated with intracoronary thrombolysis or direct percutaneous transluminal coronary angioplasty. Coronary angiography was performed every 5 min for reperfusion therapy to identify the onset of reperfusion. Reperfusion, defined as a TIMI grade 2 or 3, was achieved within 60 min of the initiation of reperfusion therapy in 30 patients (the reperfused group), but was not achieved in 15 patients (the non-reperfused group). Blood samples were obtained before initiation of treatment and 15, 30 and 60 min after initiation of treatment in the non-reperfused group. In the reperfused group, samples were obtained before reperfusion and 15, 30 and 60 min after reperfusion. The H-FABPc ratio (the ratio of value after to value before the initiation of treatment or reperfusion) increased sharply after the onset of reperfusion, peaking at 41±18 min, and decreased rapidly thereafter. The predictive accuracy of an H-FABPc ratio of > 1.8 for the detection of reperfusion within 60 min of the initiation of treatment was 93% at 15 min after reperfusion, 98% at 30 min, and 100% at 60 min. Similar rates of predictive accuracy were observed for a myoglobin ratio > 2.4. The H-FABPc ratio detected successful reperfusion as early as 15 min after the onset of reperfusion and was highly accurate in detecting reperfusion within 60 min of the onset of reperfusion. The predictive accuracy of the H-FABPc ratio was similar to that of the myoglobin ratio for the early detection of successful coronary reperfusion.