Pericytes resident in postnatal skeletal muscle differentiate into muscle fibres and generate satellite cells.

Skeletal muscle fibres form by fusion of mesoderm progenitors called myoblasts. After birth, muscle fibres do not increase in number but continue to grow in size because of fusion of satellite cells, the postnatal myogenic cells, responsible for muscle growth and regeneration. Numerous studies suggest that, on transplantation, non-myogenic cells also may contribute to muscle regeneration. However, there is currently no evidence that such a contribution represents a natural developmental option of these non-myogenic cells, rather than a consequence of experimental manipulation resulting in cell fusion. Here we show that pericytes, transgenically labelled with an inducible Alkaline Phosphatase CreERT2, but not endothelial cells, fuse with developing myofibres and enter the satellite cell compartment during unperturbed postnatal development. This contribution increases significantly during acute injury or in chronically regenerating dystrophic muscle. These data show that pericytes, resident in small vessels of skeletal muscle, contribute to its growth and regeneration during postnatal life.

Partial dysferlin reconstitution by adult murine mesoangioblasts is sufficient for full functional recovery in a murine model of dysferlinopathy.

Dysferlin deficiency leads to a peculiar form of muscular dystrophy due to a defect in sarcolemma repair and currently lacks a therapy. We developed a cell therapy protocol with wild-type adult murine mesoangioblasts. These cells differentiate with high efficiency into skeletal muscle in vitro but differ from satellite cells because they do not express Pax7. After intramuscular or intra-arterial administration to SCID/BlAJ mice, a novel model of dysferlinopathy, wild-type mesoangioblasts efficiently colonized dystrophic muscles and partially restored dysferlin expression. Nevertheless, functional assays performed on isolated single fibers from transplanted muscles showed a normal repairing ability of the membrane after laser-induced lesions; this result, which reflects gene correction of an enzymatic rather than a structural deficit, suggests that this myopathy may be easier to treat with cell or gene therapy than other forms of muscular dystrophies.

Cardiac mesoangioblasts are committed, self-renewable progenitors, associated with small vessels of juvenile mouse ventricle.

Different cardiac stem/progenitor cells have been recently identified in the post-natal heart. We describe here the identification, clonal expansion and characterization of self-renewing progenitors that differ from those previously described for high spontaneous cardiac differentiation. Unique coexpression of endothelial and pericyte markers identify these cells as cardiac mesoangioblasts and allow prospective isolation and clonal expansion from the juvenile mouse ventricle. Cardiac mesoangioblasts express many cardiac transcription factors and spontaneously differentiate into beating cardiomyocytes that assemble mature sarcomeres and express typical cardiac ion channels. Cells similarly isolated from the atrium do not spontaneously differentiate. When injected into the ventricle after coronary artery ligation, cardiac mesoangioblasts efficiently generate new myocardium in the peripheral area of the necrotic zone, as they do when grafted in the embryonic chick heart. These data identify cardiac mesoangioblasts as committed progenitors, downstream of earlier stem/progenitor cells and suitable for the cell therapy of a subset of juvenile cardiac diseases.

Complete or incomplete percutaneous coronary revascularization in patients with unstable angina in stent era: Are early and one-year results different?

The aim of our study was to evaluate the impact of a strategy of incomplete revascularization by PTCA, with or without stent implantation, on clinical outcome of 208 consecutive patients (171 men) with unstable angina and multivessel coronary artery disease. Mean age of the group was 63.8 +/- 10.3 years (range, 31-91). Complete and incomplete revascularization was achieved in 49 and 159 patients, respectively. A total of 226 stents were implanted in 172 patients (1.31 +/- 0.65 stent per patient), equally distributed between the two groups. Left ventricular ejection fraction < 40% and total chronic coronary occlusions were significantly more frequent in patients with incomplete revascularization than in those with complete (P = 0.014 and 0.001, respectively). In-hospital MACE occurred in 10% and 7.5% of patients with complete and incomplete revascularization, respectively (P = NS). By multivariate analysis, multiple stent implantation (OR, 5.44; 95% CI, 1.21-24.3), presence of thrombus in the treated lesion (OR, 6.3; 95% CI, 1.53-25.9), Braunwald class III (OR, 4.74; 95% CI, 1.08-20.8), and ad hoc PTCA (OR 4.51; 95% CI, 1.11-18.3) were significantly related to in-hospital outcome. At 1-year follow-up, 11.3% and 11.5% of patients with complete and incomplete revascularization, respectively, had MACE. In all patients, diabetes (OR, 3.40; 95% CI, 1.09-10.58) and presence of thrombus in the treated lesion (OR, 3.48; 95% CI, 1.12-10.84) were significant predictors of 1-year outcome by multivariate analysis. These results indicate that the strategy of incomplete revascularization in unstable angina patients with multivessel coronary disease does not expose them to a higher risk of death or other major ischemic events in comparison to those undergoing complete revascularization.

Coronary angioplasty in patients with unstable angina: clinical, electrocardiographic and angiographic predictors of in-hospital outcome. R.OS.A.I. Study Group.

BACKGROUND: In unstable angina early coronary arteriography is frequently performed, often followed by percutaneous revascularization with liberal use of stents. We intended to study the in-hospital outcome of patients receiving this treatment. METHODS: From April 1997 to April 1998, patients submitted to coronary arteriography due to unstable angina, and with no previous myocardial revascularization, were included in a multicenter registry. RESULTS: Out of 987 patients enrolled at 14 centers, 876 (89%) had percutaneous or surgical revascularization. Coronary angioplasty was performed in 571 patients (58%); 281 (49%) had Braunwald class IIIB or C angina. Refractory or prolonged chest pain, or both, were present in 133, 217 and 85 patients, respectively, and multivessel disease in 245 patients (43%). Stenting was performed in 486/571 cases (85%), abciximab was administered to 42 patients, and ticlopidine and/or aspirin to all. A procedural success was obtained in 96.9 % of cases. In-hospital major adverse cardiac events occurred in 29/571 patients (5.1%). Pain-related ST segment depression (44% of cases) was not predictive of outcome after coronary angioplasty. In multivariate analysis prolonged plus refractory angina (p = 0.02), an ejection fraction < 0.4 (p = 0.04), multivessel disease (p = 0.01) and--with the strongest predictive value--ad hoc angioplasty (p = 0.007) and use of > 1 stent (p = 0.0008) were all independent predictors of in-hospital adverse outcome. CONCLUSIONS: Coronary angioplasty with a liberal use of stents yields a high rate of procedural success, with few in-hospital major cardiac events also in "high risk" patients.

Angiographic follow-up after coronary implantation of the Multilink stent: a prospective observation.

BACKGROUND: A growing variety of coronary stents is becoming available on the market. Results of randomized trials may be difficult to apply to less selected patients, and experience with every device cannot be obtained in every center. Detailed information about the immediate and long-term results achieved with one device can be a helpful reference for interventional cardiologists. The aim of this study was to test the applicability and the clinical and angiographic results, both immediate and at 6 months, of the Multilink coronary stent in a cohort of unselected patients undergoing coronary angioplasty. METHODS: From March 1997 to June 1998 coronary angioplasty was performed in 391 patients in our center, with the use of stents in 339 patients. RESULTS: Three hundred and seventeen Multilink stents were successfully implanted in 295 lesions in 277 patients; an acute coronary syndrome was present in 209 cases (75%), and lesion types B2 and C accounted for 30% of lesions. In 7 cases (2.4%) the Multilink stent did not cross the lesion, and another device was implanted. Subacute stent occlusion occurred in 1 patient (0.36%) after primary angioplasty. After 6 months from the procedure, clinical follow-up data were available for 252 out of 254 patients: none had died, and angina or myocardial ischemia occurred in 25 patients (9.9%). A control angiogram was performed in 239 out of 254 patients (94%) at 178 +/- 34 days. Restenosis occurred in 44/239 patients (18.4%) and in 48/247 lesions (19.4%). In patients with vs without restenosis the original lesion was longer (p = 0.009), and diabetes mellitus was more frequent (p = 0.002), as was the use of multiple stents (p = 0.005). In single 15, 25 and 35 mm long stents restenosis occurred in 13.9, 15.5 and 46.2% of cases, respectively (p = NS). CONCLUSIONS: The Multilink stent showed a low rate of subacute occlusion (0.36%) and could be used safely also in patients with acute coronary syndromes. The use of a single, 15 or 25 mm long Multilink stent was associated with a low angiographic recurrence rate (14-16%).

Myocardial infarction with acute thrombosis of multiple major coronary arteries: a clinical and angiographic observation in four patients.

Four patients are reported in whom concomitant obstructive thrombosis of two major coronary vessels was observed at coronary angiography during evolving myocardial infarction. In all cases the simultaneous involvement of both vessels as the cause of acute ischemia was confirmed by the results of sequential treatment of the lesions with emergency angioplasty.

[Heart catheterization via the femoral artery with a 4 French and mobilization at 2 hours]. / Cateterismo cardiaco per via arteriosa femorale con 4 French e mobilizzazione a 2 ore.

The use of small catheters for cardiac catheterization, as well as for other diagnostic and interventional procedures, can reduce iatrogenic trauma on cardiac and vascular structures. Early patient mobilization may thus reduce both patient discomfort and the length and cost of stays. The performance of 4 French catheters was evaluated in a pilot cohort of consecutive in patients who underwent coronary arteriography with the use of the femoral Judkins technique and who had no restriction to full ambulation. Patients were helped to resume full ambulation two hours after the procedure, and the femoral access site was inspected 24 hours later upon discharge. Coronary arteriography with 4 French catheters was performed in 45 patients (10 women) aged 62 +/- 10 years. In one patient with anomalous origin of the right coronary artery, selective catheterization of the coronary ostium required a catheter style available only in 5 French. In all cases, selective opacification with 4 French catheters was adequate for diagnosis. Forty-three patients were mobilized 115 +/- 10 minutes after the end of manual compression. Hematoma, bleeding or limb perfusion disturbances were absent in all cases upon inspection 22 +/- 4 hours later. This pilot experience indicates that coronary arteriography with femoral 4 French Judkins catheters is technically feasible and that patient ambulation 2 hours later is safe. This data requires confirmation in a larger patient cohort and can lead to new standards for both patient comfort and the use of hospital resources in coronary arteriography.

Comparison of thrombolytic therapy and primary coronary angioplasty with liberal stenting for inferior myocardial infarction with precordial ST-segment depression: immediate and long-term results of a randomized study.

OBJECTIVES: The aim of the study was to compare randomly assigned primary angioplasty and accelerated recombinant tissue plasminogen activator (rt-PA), in patients with "high-risk" inferior acute myocardial infarction (ST-segment elevation in the inferior leads and ST-segment depression in the precordial leads). BACKGROUND: The ST-segment depression in the precordial leads is a marker of severe prognosis in patients with inferior myocardial infarction. The comparative outcome of treatment with primary angioplasty or lysis with accelerated rt-PA has not been investigated. METHODS: One hundred and ten patients within 6 h of symptoms were randomized to either treatment. To assess the in-hospital and 1-year outcome of both treatments the following results were compared: death or nonfatal infarction, recurrence of angina, left ventricular ejection fraction (LVEF), and the need for repeat target vessel revascularization (TVR). RESULTS: In patients treated with angioplasty (55) and rt-PA (55) the rate of in-hospital mortality and reinfarction was 3.6% versus 9.1% (p=0.4). Recurrence of angina was 1.8% versus 20% (p=0.002), new TVR was used in 3.6% versus 29.1% (p=0.0003), and the LVEF (%) at discharge was 55.2+/-9.5 versus 48.2+/-9.9 (p=0.0001). There were no hemorrhagic strokes, no emergency coronary artery bypass graft (CABG) and identical (5.5%) need for blood transfusions. At 1 year, the incidence of death, reinfarction or repeat TVR was 11% in the percutaneous transluminal coronary angioplasty (PTCA) group versus 52.7% in the rt-PA group (log-rank 22.38, p < 0.0001). CONCLUSIONS: Primary angioplasty is superior to accelerated rt-PA in terms of both myocardial preservation and reduction of in-hospital complications in patients with inferior myocardial infarction and precordial ST-segment depression. Primary angioplasty also yields a better long-term event-free survival.

[Primary angioplasty in acute inferior myocardial infarct with anterior ST-segment depression: the long-term follow-up]. / Angioplastica primaria nell'infarto miocardico acuto inferiore con sottoslivellamento anteriore del tratto ST: follow-up a lungo termine.

BACKGROUND: Concomitant anterior ST-segment depression is a marker of severe prognosis in inferior myocardial infarction. PATIENTS AND METHODS: Prospective observational study in patients with inferior acute myocardial infarction and ST-segment depression > or = 4 mm in the anterior leads, who were treated with primary angioplasty. Angiography was performed at hospital discharge and at six months, and a clinical follow-up was obtained at one year after the infarction. RESULTS: Sixty-three patients were included in the study. Pre-hospital and in-hospital delay were 147 +/- 70 minutes (20-355) and 54 +/- 11 minutes (18-80), respectively. Angioplasty was successful in all patients and 48 stents were implanted in 36 patients (57%). Angiography was performed at hospital discharge in 55 patients (87%) and showed a TIMI grade 3 coronary flow in the infarct-related artery in all cases. The left ventricular ejection fraction was 0.55 +/- 0.09 (0.4-0.8). One patient (1.6%) died before discharge, two (3.2%) had ischemic complications (one had non-fatal reinfarction, another had recurrent angina at rest), and three (4.9%) had local vascular complications. At the six-month follow-up, none of the patients had died. One had suffered reinfarction (1.6%) and another had been readmitted for recurrence of angina at rest (1.6%); none had symptoms of stable angina. The ejection fraction was 0.56 +/- 0.12 and eight patients (14%) showed angiographic restenosis. At twelve months, two patients had died (1.6%) and five (8%) had required readmission to hospital. CONCLUSIONS: Primary angioplasty yielded favorable results in this group of patients. Our data confirm the efficacy of primary angioplasty for the treatment of acute myocardial infarction, with a low rate of clinical (3.2%) and angiographic (14%) restenosis at six months, and a high rate (87%) of event-free survival at one year follow-up.

Plasma lipoprotein(a) is not a predictor for restenosis after elective high-pressure coronary stenting.

BACKGROUND: Lipoprotein(a) is a risk factor for coronary artery disease. Although it has been implicated in restenosis after balloon angioplasty, its role in restenosis within coronary stents is unknown. The aim of the study was to assess the role of plasma lipoprotein(a) as a predictor for restenosis after elective coronary stenting. METHODS AND RESULTS: Elective, high-pressure stenting of de novo lesions in native coronary arteries with Palmaz-Schatz stents was performed in 325 consecutive patients. Clinical, angiographic, and biochemical data were analyzed prospectively. Angiographic follow-up was performed at 6 months. Lipoprotein(a) levels were compared in patients with and without restenosis. Angiographic follow-up was obtained in 312 patients (96%); recurrence was observed in 67 patients (21.5%). No clinical or biochemical variable was associated with restenosis. Lipoprotein(a) level was 37.81+/-49. 01 mg/dL (median, 22 mg/dL; range, 3 to 262 mg/dL) in restenotic patients and 36.95+/-40.65 mg/dL (median, 22 mg/dL; range, 0 to 244 mg/dL) in nonrestenotic patients (P=NS). The correlations between percent diameter stenosis, minimum luminal diameter, and late loss at follow-up angiography and basal lipoprotein(a) plasma level after logarithmic transformation were 0.006, 0.002, and 0.0017, respectively. Multiple stents were associated with a higher incidence of restenosis (P=0.006), but biochemical data in these patients were similar to those treated with single stents. CONCLUSIONS: The basal plasma level of lipoprotein(a) measured before the procedure is not a predictor for restenosis after elective high-pressure coronary stenting.

Use of Gianturco-Roubin stents for treating abrupt occlusion of unprotected left main stem during elective PTCA.

Abrupt occlusion of the left main during elective coronary angioplasty has a high mortality rate despite emergent surgery. Coronary stents are useful for managing abrupt occlusion during balloon angioplasty, but patients treated with bail-out stenting to obviate life-threatening occlusions are usually operated after stabilization. Two cases of multiple bail-out stenting of the left main as a stand-alone treatment and their long-term follow-up are reported.

Early aggressive treatment of unstable angina without on-site cardiac surgical facilities: a prospective study of acute and long-term outcome.

BACKGROUND: The early invasive diagnostic approach with extensive use of myocardial revascularization in patients with unstable angina is a matter of debate. Both the advantages of this strategy and the choice of the best candidates are controversial. The widespread applicability of this approach in Italian hospitals is also questionable, due to limited availability of facilities for interventional cardiology. METHODS: A prospective, observational study was done on a cohort of consecutive patients, who were admitted with a diagnosis of unstable angina and treated with an early aggressive approach at a center with interventional cardiology facilities without cardiac surgery. The aim of the study was to evaluate both the immediate and long-term clinical outcome of patients and the efficiency of our therapeutic approach. RESULTS: Two-hundred and two patients were enrolled and 85% were in Braunwald class III. Coronary angiography was performed in 171 patients (85%) at 2.1 +/- 2.4 days after admission: it showed one-, two- and three-vessel disease in 40, 29 and 22% of cases, respectively; 9% of patients had no severe coronary lesion. Left ventricular ejection fraction was 0.58 +/- 0.13. Medical treatment, coronary by-pass surgery and percutaneous myocardial revascularization were chosen in 36, 24 and 40% of cases, respectively. Coronary angioplasty was performed in our center in 58 (73%) of 80 patients at 6.8 +/- 5.6 days after admission and stents were used in 42 cases (74%). Overall hospital stay was 10.4 +/- 4 days. Cumulated adverse events (death and non-fatal myocardial infarction) occurred in 2.5 and 7% of patients during the initial admission and in the following year, respectively. CONCLUSIONS: An early aggressive approach to patients with unstable angina is feasible in a hospital with interventional cardiology in the absence of cardiac surgical facilities. The immediate favorable clinical results of this strategy in an intermediate-risk cohort seem to persist at one-year follow-up.

Prevalence of late potentials after myocardial infarction treated with systemic thrombolysis or primary percutaneous transluminal coronary angioplasty.

BACKGROUND: The presence of late potentials (LP) after myocardial infarction (MI) is related to an occluded infarct-related coronary artery (IRA). However, the effects of the signal-averaged electrocardiogram (SAECG) of systemic thrombolysis are contradicting. Reperfusion in the IRA is more frequently observed after primary percutaneous transluminal coronary angioplasty (PTCA) than after systemic thrombolysis. The aim of this prospective study was to compare the prevalence of LP in survivors of acute MI treated with either systemic thrombolysis or primary PTCA. METHODS: Between October 1994 and January 1997, 134 patients (pts) with acute MI were treated with reperfusion therapy within 12 hours of the onset of symptoms: seventy-four pts received systemic thrombolysis and 60 underwent primary PTCA. All pts (mean age 61 +/- 10 years, 120 males) had a control coronary angiography 9 +/- 5 and 10 +/- 4 days after acute MI, respectively. The recorded signals were amplified, averaged and filtered with bi-directional Butterworth filtering (band-pass filter range of 40-250 Hz). LPs were defined as the presence of 2 or 3 of the following criteria: filtered duration of the QRS complex > 114 ms, root mean square voltage of signals in the last 40 ms of the QRS < or = 20 mV and duration of the low amplitude signals > 38 ms. RESULTS: The two groups of pts did not differ significantly with respect to age, gender, presence of either diabetes or hypertension, site of MI, previous MI, Killip class, time to treatment, peak CK-MB level, incidence of reinfarction, extent of coronary artery disease and left ventricular ejection fraction. One hundred pts (75%) had patency (TIMI 3 grade flow) of the IRA at control coronary angiography. Twenty-seven pts (20%) had LP: 16 pts (22%) among those treated with systemic thrombolysis and 11 pts (18%) among those treated with primary PTCA (p = ns). Pts treated with primary PTCA had higher patency rates [95% (57/60) vs 58% (43/74); p = 0.00002] and less severe residual stenosis (19 +/- 15% vs 72 +/- 18%; p = 0.0001) in the IRA. LP were found in 15 pts (15%) with TIMI 3 grade flow and in 12 pts (35%) with TIMI 0-2 grade flow (p = 0.017). By multivariate analysis, including 18 clinical and electrocardiographic variables, an occluded IRA was the only independent predictor of the development of LP (Wald chi 2: 6.1453; p = 0.0132). CONCLUSION: Results of this prospective study suggest that primary PTCA alone does not reduce the prevalence of LP when compared to systemic thrombolysis. Only the patency of the IRA, as determined before the hospital discharge, affected the development of LP after acute MI.

Plasma activity and insertion/deletion polymorphism of angiotensin I-converting enzyme: a major risk factor and a marker of risk for coronary stent restenosis.

BACKGROUND: Tissue proliferation is almost invariably observed in recurrent lesions within stents, and ACE, a factor of smooth muscle cell proliferation, may play an important role. Plasma ACE level is largely controlled by the insertion/deletion (I/D) polymorphism of the enzyme gene. The association among restenosis within coronary stents, plasma ACE level, and the I/D polymorphism is analyzed in the present prospective study. METHODS AND RESULTS: One hundred seventy-six consecutive patients with successful, high-pressure, elective stenting of de novo lesions in the native coronary vessels were considered. At follow-up angiography, recurrence was observed in 35 patients (19.9%). Baseline clinical and demographic variables, plasma glucose and serum fibrinogen levels, lipid profile, descriptive and quantitative angiographic data, and procedural variables were not significantly different in patients with and without restenosis; mean plasma ACE levels (+/-SEM) were 40.8+/-3.5 and 20.7+/-1.0 U/L, respectively (P<.0001). Diameter stenosis percentage and minimum luminal diameter at 6 months showed statistically significant correlation with plasma ACE level (r=.352 and -.387, respectively P<.001). Twenty-one of 62 patients (33.9%) with D/D genotype, 13 of 80 (16.3%) with I/D genotype, and 1 of 34 (2.9%) with I/I genotype showed recurrence; the restenosis rate for each genotype is consistent with a codominant expression of the allele D. CONCLUSIONS: In a selected cohort of patients, both the D/D genotype of the ACE gene, and high plasma activity of the enzyme are significantly associated with in-stent restenosis. Continued study with clinically different subsets of patients and various stent designs is warranted.

[The Registry for Angioplasty in Infarction (RAI): brief preliminary report on the main indicators and process of acute outcome]. / Registro per l'Angioplastica nell'Infarto (RAI): breve report preliminare dei principali indicatori di processo e di esito acuto. Conto di Tutti i Ricercatori del RAI.

BACKGROUND: Emergency coronary angioplasty can be the treatment of choice in selected patients with acute myocardial infarction in centers with adequate facilities and organization. METHODS: A multicenter observational study in patients with high-risk acute myocardial infarction was conducted to evaluate the quality of emergency angioplasty treatment according to process, acute and long-term outcome, and use of resources. RESULTS: The RAI registry included 345 patients with high-risk acute myocardial infarction who were admitted to six participating centers over a thirteen-month period. Emergency coronary angiography was performed in 261 patients (76%) and was followed by immediate angioplasty in 236 of them (68%). Mean door-to-procedure time was 58 +/- 47 min. Severe left ventricular failure was present at admission in 35 (13%) of the 261 patients with emergency coronary angiography; and 29 of them were in cardiogenic shock (11%). Overall, in-hospital mortality for patients with angioplasty was 7.6%; i.e., 43% and 3.7% for patients with and without shock, respectively. CONCLUSIONS: Despite logistical limitation, in centers with emergency angioplasty programs this treatment can be performed with favorable process and acute outcome characteristics in patients with high-risk myocardial infarction.

[Effects on high resolution electrocardiogram of coronary angioplasty in acute myocardial infarct]. / Effetti sull'elettrocardiogramma ad alta risoluzione dell'angioplastica coronarica nell'infarto miocardico acuto.

BACKGROUND: The lower prevalence of ventricular late potentials (LPs) in signal-averaged electrocardiograms (SAECG) observed in patients (pts) treated with systemic thrombolysis, as compared with SAECGs in conventionally treated pts, has been attributed to the patency of the infarct-related artery. Mechanical reperfusion, achieved by means of either primary or rescue percutaneous transluminal coronary angioplasty (PTCA), is associated with higher permeability rates and reduced residual stenosis in the infarct-related artery, when compared to systemic thrombolysis. The aim of this retrospective study was to assess the prevalence of LPs in pts recovering from a first high-risk acute myocardial infarction (AMI) treated with primary or rescue PTCA. METHODS: Fifty-nine pts (48 pts with clinical signs or electrocardiographic evidence of high-risk AMI or in whom systemic thrombolysis was inadvisable, and 11 pts in whom systemic thrombolysis failed) underwent emergency PTCA within 10 hours of the onset of symptoms. All pts (mean age 61 +/- 9 years, 48 M) were monitored via coronary angiography 9 +/- 4 days after AMI. The SAECG was obtained 10 +/- 4 days after AMI. LPs were defined as the presence of 2 or 3 of the following criteria: filtered duration of the QRS complex > 114 ms, duration of the low amplitude signals > 38 ms and mean square-root voltage of signals in the last 40 ms of the QRS < or = 20 microV. RESULTS: Primary and rescue PTCA were performed 3 +/- 1.7 and 6.3 +/- 2 hours after AMI, respectively (p = 0.000). Fifty-six pts (95%) had patency (TIMI 3 grade flow) of the infarct-related artery (mean residual stenosis: 18.3 +/- 14.2%) confirmed by control coronary angiography, while the infarct-related artery was occluded in three pts. Sixteen out of 59 pts (27%) had LPs: 14/56 (25%) with TIMI 3 grade flow and 2/3 (67%) with TIMI 0 grade flow. Pts with and without LPs were comparable for age, sex, infarct location, Killip Class, mean peak CK-MB, time to control coronary angiography, time to SAECG, left ventricular ejection fraction, presence of multivessel disease, infarct-related artery and mean residual stenosis in infarct-related artery. LPs were observed more frequently after rescue PTCA than after primary PTCA (64 vs 19%; p = 0.005). Time to treatment was significantly longer in pts with LPs than in those without (4.9 +/- 2.6 vs 3.2 +/- 1.7 hours; p = 0.025). Multivariate analysis indicated that the type of PTCA (primary vs rescue PTCA) was the only independent predictor for the development of LPs. CONCLUSION: In this study, the prevalence of LPs in pts with patency of the infarct-related artery after primary or rescue PTCA was surprisingly high. Delay to treatment and type of PTCA affected the presence of LPs. The association between infarct-related artery status and prevalence of LPs has not been analyzed, due to the low number of pts with coronary artery occlusion in the control coronary angiography.

Coronary stenting after unsuccessful emergency angioplasty in acute myocardial infarction: results in a series of consecutive patients.

Nineteen consecutive procedures of coronary stenting were attempted in 70 consecutive patients (27%) with evolving myocardial infarction due to threatened vessel reocclusion after primary (16 cases) or rescue (3 cases) angioplasty. Two patients were in cardiogenic shock. Stent delivery was successful in 18 patients, with a Thrombolysis in Myocardial infarction flow grade 3; residual diameter stenosis and minimum luminal diameter were 19% +/- 11% and 2.96 +/- 0.62 mm, respectively. After the procedure, heparin was continued for 4 days and 250 mg ticlopidine twice a day for 1 month. Acute stent occlusion occurred in one patient 1 hour after the procedure and was successfully treated with emergency repeat angioplasty. Subacute stent occlusion occurred 6 days after the procedure in one patient, with multivessel coronary disease and a suboptimal stent result. He had been referred for surgery, and emergent coronary artery bypass was performed. Coronary bypass surgery was performed in another patient before discharge because of severe multivessel disease. Persistent cardiogenic shock and new myocardial infarction in another location were the causes of death in two patients, 3 and 10 days after the procedure, respectively. Fifteen patients were discharged with a patient infarct vessel and without reinfarction or need for coronary bypass surgery. One patient had repeat angioplasty for intrastent restenosis at 3 months. The remaining 14 patients were free from new coronary events 4 +/- 2 months after the procedure. Although acute myocardial infarction is generally considered a contraindication to the use of coronary stents, stents may play a role in increasing the rates of successful infarct artery reperfusion.

Short communication: staff dose reduction during coronary angiography using low framing speed.

Radiation exposure of cardiac catheterization laboratory staff is a known occupational hazard, and efforts are made to obtain dose levels which are "as low as reasonably achievable". This study assessed the reduction in staff radiation exposure using cine framing at 12.5 f s-1 during coronary cineangiography, instead of 25 f s-1. Thermoluminescent dosemeters were used to measure equivalent dose at several sites for the operator, nurse assistant, and X-ray technician during 15 procedures at both frame rates. Patient-related and procedure-related variables were similar in the two groups of examinations. Mean equivalent dose absorbed (microSv) at the left side of the forehead was reduced by 61%, 60% and 36%, for the operator, nurse assistant and X-ray technician, respectively. With use of the lower frame rate similar reductions by 42%, 62% and 62% were measured at the thyroid level, and by 51%, 40% and 61% at the mid-thorax level. Cinefilming at low frame rates during coronary arteriography allows a substantial X-ray dose reduction at all body sites for all staff. Use of lower frame rates wherever possible is of special interest since it may also reduce patient radiation exposure.