Mesoangioblasts at 20: From the embryonic aorta to the patient bed

In 2002 we published an article describing a population of vessel-associated progenitors that we termed mesoangioblasts (MABs). During the past decade evidence had accumulated that during muscle development and regeneration things may be more complex than a simple sequence of binary choices (e.g., dorsal vs. ventral somite). LacZ expressing fibroblasts could fuse with unlabelled myoblasts but not among themselves or with other cell types. Bone marrow derived, circulating progenitors were able to participate in muscle regeneration, though in very small percentage. Searching for the embryonic origin of these progenitors, we identified them as originating at least in part from the embryonic aorta and, at later stages, from the microvasculature of skeletal muscle. While continuing to investigate origin and fate of MABs, the fact that they could be expanded in vitro (also from human muscle) and cross the vessel wall, suggested a protocol for the cell therapy of muscular dystrophies. We tested this protocol in mice and dogs before proceeding to the first clinical trial on Duchenne Muscular Dystrophy patients that showed safety but minimal efficacy. In the last years, we have worked to overcome the problem of low engraftment and tried to understand their role as auxiliary myogenic progenitors during development and regeneration.

Hemogenic endothelium generates mesoangioblasts that contribute to several mesodermal lineages in vivo

The embryonic endothelium is a known source of hematopoietic stem cells. Moreover, vessel-associated progenitors/stem cells with multilineage mesodermal differentiation potential, such as the ‘embryonic mesoangioblasts’, originate in vitro from the endothelium. Using a genetic lineage tracing approach, we show that early extra-embryonic endothelium generates, in a narrow time-window and prior to the hemogenic endothelium in the major embryonic arteries, hematopoietic cells that migrate to the embryo proper, and are subsequently found within the mesenchyme. A subpopulation of these cells, distinct from embryonic macrophages, co-expresses mesenchymal and hematopoietic markers. In addition, hemogenic endothelium-derived cells contribute to skeletal and smooth muscle, and to other mesodermal cells in vivo, and display features of embryonic mesoangioblasts in vitro. Therefore, we provide new insights on the distinctive characteristics of the extra-embryonic and embryonic hemogenic endothelium, and we identify the putative in vivo counterpart of embryonic mesoangioblasts, suggesting their identity and developmental ontogeny.

Alpha sarcoglycan is required for FGF-dependent myogenic progenitor cell proliferation in vitro and in vivo

Mice deficient in α-sarcoglycan (Sgca-null mice) develop progressive muscular dystrophy and serve as a model for human limb girdle muscular dystrophy type 2D. Sgca-null mice suffer a more severe myopathy than that of mdx mice, the model for Duchenne muscular dystrophy. This is the opposite of what is observed in humans and the reason for this is unknown. In an attempt to understand the cellular basis of this severe muscular dystrophy, we isolated clonal populations of myogenic progenitor cells (MPCs), the resident postnatal muscle progenitors of dystrophic and wild-type mice. MPCs from Sgca-null mice generated much smaller clones than MPCs from wild-type or mdx dystrophic mice. Impaired proliferation of Sgca-null myogenic precursors was confirmed by single fiber analysis and this difference correlated with Sgca expression during MPC proliferation. In the absence of dystrophin and associated proteins, which are only expressed after differentiation, SGCA complexes with and stabilizes FGFR1. Deficiency of Sgca leads to an absence of FGFR1 expression at the membrane and impaired MPC proliferation in response to bFGF. The low proliferation rate of Sgca-null MPCs was rescued by transduction with Sgca-expressing lentiviral vectors. When transplanted into dystrophic muscle, Sgca-null MPCs exhibited reduced engraftment. The reduced proliferative ability of Sgca-null MPCs explains, at least in part, the severity of this muscular dystrophy and also why wild-type donor progenitor cells engraft efficiently and consequently ameliorate disease.

Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells

Skeletal muscle damaged by injury or by degenerative diseases such as muscular dystrophy is able to regenerate new muscle fibers. Regeneration mainly depends upon satellite cells, myogenic progenitors localized between the basal lamina and the muscle fiber membrane. However, other cell types outside the basal lamina, such as pericytes, also have myogenic potency. Here, we discuss the main properties of satellite cells and other myogenic progenitors as well as recent efforts to obtain myogenic cells from pluripotent stem cells for patient-tailored cell therapy. Clinical trials utilizing these cells to treat muscular dystrophies, heart failure, and stress urinary incontinence are also briefly outlined.

Isolation and characterization of mesoangioblasts from mouse, dog, and human tissues

Mesoangioblasts are recently identified stem/progenitor cells, associated with small vessels of the mesoderm in mammals. Originally described in the mouse embryonic dorsal aorta, similar though not identical cells have been later identified and characterized from postnatal small vessels of skeletal muscle and heart (not described in this unit). They have in common the anatomical location, the expression of endothelial and/or pericyte markers, the ability to proliferate in culture, and the ability to undergo differentiation into various types of mesoderm cells upon proper culture conditions. Currently, the developmental origin of mesoangioblasts, their phenotypic heterogeneity, and the relationship with other mesoderm stem cells are not understood in detail and are the subject of active research. However, from a practical point of view, these cells have been successfully used in cell transplantation protocols that have yielded a significant rescue of structure and function in skeletal muscle of dystrophic mice and dogs. Since the corresponding human cells have been recently isolated and characterized, a clinical trial with these cells is planned in the near future. This unit provides detailed methods for isolation, culture, and characterization of mesoangioblasts.

Pericytes of human skeletal muscle are myogenic precursors distinct from satellite cells

Cells derived from blood vessels of human skeletal muscle can regenerate skeletal muscle, similarly to embryonic mesoangioblasts. However, adult cells do not express endothelial markers, but instead express markers of pericytes, such as NG2 proteoglycan and alkaline phosphatase (ALP), and can be prospectively isolated from freshly dissociated ALP(+) cells. Unlike canonical myogenic precursors (satellite cells), pericyte-derived cells express myogenic markers only in differentiated myotubes, which they form spontaneously with high efficiency. When transplanted into severe combined immune deficient-X-linked, mouse muscular dystrophy (scid-mdx) mice, pericyte-derived cells colonize host muscle and generate numerous fibres expressing human dystrophin. Similar cells isolated from Duchenne patients, and engineered to express human mini-dystrophin, also give rise to many dystrophin-positive fibres in vivo. These data show that myogenic precursors, distinct from satellite cells, are associated with microvascular walls in the human skeletal muscle, may represent a correlate of embryonic 'mesoangioblasts' present after birth and may be a promising candidate for future cell-therapy protocols in patients.

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.

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.

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%).

[Heart catheterization via the femoral artery with a 4 French and mobilization at 2 hours]

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.

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.

[Primary angioplasty in acute inferior myocardial infarct with anterior ST-segment depression: the long-term follow-up]

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.

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.

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.

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.

[Effects on high resolution electrocardiogram of coronary angioplasty in acute myocardial infarct]

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.

[The Registry for Angioplasty in Infarction (RAI): brief preliminary report on the main indicators and process of acute outcome]

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.

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.

Ambulation three hours after elective cardiac catheterisation through the femoral artery

OBJECTIVE

To test whether very early resumption of ambulation after femoral cardiac catheterisation is feasible and safe in patients with stable symptoms.

DESIGN

Prospective study in a selected group of men and women undergoing elective cardiac catheterisation, with next day physical inspection.

SETTING

Inpatient study.

SUBJECTS

Two hundred consecutive ambulant patients submitted to diagnostic cardiac catheterisation through the femoral arterial route using 5F catheters: a femoral right heart study was done at the same time in 40 patients (20%).

RESULTS

No patient had major complications during the study. Early ambulation was not allowed in two patients (1%) because of haematoma formation immediately after sheath removal, and in seven (3%) because of poor haemostasis or haematoma on inspection at 3 h. Early ambulation was interrupted in two patients (1%) because of transient arterial hypotension on standing in one, and the patient's preference in the other. Of 189 patients who resumed full ambulation at 3 h, one (0.5%) had a groin haematoma on discharge the next morning. Overall, haematoma 12 h after cardiac catheterisation was present in seven of the 200 patients initially included in the study (3.5%). None of the 191 patients with attempted early mobilisation had signs or symptoms of vascular complications one month or later after discharge.

CONCLUSION

Supervised resumption of ambulation 3 h after uncomplicated cardiac studies with 5F femoral arterial catheters is safe and feasible in most ambulant patients undergoing elective cardiac catheterisation.

[Radiologic practice and radioprotection in Italian hemodynamic laboratories]

Increasing numbers of diagnostic and therapeutic cardiac catheterization procedures are performed in Italy each year. Radiation exposure of the cardiac catheterization laboratory staff is a known hazard, and there is growing public and professional concern over the risks of low-energy medical ionizing radiation for the patients. The aim of this study was to outline the range of current radiological and radiation protection practice in large-volume cardiac catheterization laboratories in Italy. In August 1994 a questionnaire was submitted to the chief invasive cardiologist of the 32 cardiac catheterization laboratories nation-wide having performed at least 1000 procedures in 1993. All laboratories responded. There were variations in both the radiologic technique (cine framing speed, mean film lengths and fluoroscopy times) and the radiation protection practice (use of shields, leaded collars and glasses, and sites where dosimeters are worn). In 22 of 32 laboratories the cardiologists were not aware of radiation exposure data, and only 6 laboratories could quote the exposure provided by their X-ray system or estimates of the dose absorbed by patients during diagnostic or therapeutic procedures. The results of this survey indicate that radiological practice, and techniques for measuring and reducing exposure of the personnel vary widely in cardiac catheterization laboratories in Italy. These data suggest also that reducing patients' radiation exposure is not, in general, considered to be a quality assurance priority by interventional cardiologists.

Elective coronary angioplasty with and without surgical standby: clinical and angiographic criteria for the selection of patients

BACKGROUND

The cardiac catheterization laboratory (CCL) of our hospital is the only facility for invasive cardiology in a large district. No cardiac surgery is carried out in our hospital at present, the nearest facility being approximately 50 miles away.

METHODS

Over a period of 2 years we recommended percutaneous transluminal coronary angioplasty (PTCA) with surgical standby for 164 cases, who were referred to CCLs with on-site surgical standby, and PTCA without surgical standby for 232 cases, 199 of whom underwent PTCA in our CCL. Criteria used in the selection of patients for PTCA without surgical standby were the following: (a) either limited extent or severely impaired function of the ventricular segment in jeopardy; (b) normal or near-normal function of the uninvolved myocardial segments; (c) absence of lesions of the left main or left anterior descending coronary arteries when the target stenosis was in the left coronary artery; (d) non-applicability and high risk-benefit ratio of emergency surgical revascularization in the individual patient. Clinical and angiographic characteristics of patients assigned to PTCA with and without surgical standby are compared.

RESULTS

An initial success was achieved in 186 cases (93%) in our CCL. In 12 cases (6%), PTCA was not successful, and in two cases (1%) it was complicated by myocardial infarction. None of the patients died, or had to undergo further coronary interventions within 1 month. Coronary stents were implanted in 24 cases.

CONCLUSION

For many PTCA candidates, emergency coronary surgery is not an option in case of occlusive complications. Our data suggest that PTCA can be performed with minor complications in these patients in the absence of surgical standby, provided strict criteria are used in the selection of cases.

[Emergency angioplasty in high-risk acute infarct]

BACKGROUND

Primary coronary angioplasty in acute myocardial infarction yields superior results in terms of effective vessel patency, recurrent ischemia and acute morbidity, as compared to intravenous thrombolysis. Despite obvious logistic and economic limitations, this early invasive approach could be strictly indicated in selected groups of patients.

AIM

A prospective study to test the immediate and short-term results of an early invasive strategy with angioplasty in patients with high-risk acute myocardial infarction.

METHODS

Forty-one consecutive patients with high-risk acute myocardial infarction were submitted to coronary angiography and angioplasty of the involved vessel within 12 hours of onset of symptoms. Twenty-eight had anterior myocardial infarction and 6 were in cardiogenic shock.

RESULTS

Primary success was achieved in 38 patients (93%): 30 of these were discharged without complications or further revascularization procedures, and none has symptoms or re-infarction at one-month follow-up.

CONCLUSIONS

Immediate invasive treatment with angioplasty in high-risk acute myocardial infarction seems to achieve good results, due to both effective infarct vessel recanalization, and early identification of candidates to urgent complete surgical revascularization.

[The use of activated clotting time (ACT) to optimize heparinization during coronary angioplasty. The nursing personnel of the Hemodynamics Laboratory]

BACKGROUND

Suboptimal anticoagulation during coronary angioplasty is reported to be a major risk factor for occlusive complications.

AIM

To define an appropriate timing for activated clotting time (ACT) tests in order to optimize anticoagulation with heparin during coronary angioplasty.

METHODS

In 50 consecutive procedures of elective angioplasty ACT was measured at baseline, at 30, 60 and 120 min after heparin 10,000 U iv. In a subgroup of 25 patients (SG1) no additional heparin was given until the ACT test at 60 min. In a second subgroup of 25 patients (SG2) heparin 5,000 U was administered 30-45 min after the initial bolus if the ACT at 30 min was < 300 sec. ACT values were analyzed, and the correlation with the biological variables of patients was tested.

RESULTS

In 20 patients out of 50 (40%) ACT values at 30 min were < 275 min. Heparin response was correlated with the body surface area but nor with age, neither with baseline ACT. Values at 60 min showed an adequate anticoagulation in only 6 patients (24%) in SG1 vs 21 (84%) in SG2. There were not complications.

CONCLUSIONS

ACT testing 30 min after heparin 10,000 U during coronary angioplasty identifies most patients requiring early supplemental heparin. This yields an adequate anticoagulation at 60 min in most patients.

Concomitant myocardial infarction in identical twins with similar coronary lesions

Two 42-year-old male twins were referred to our hospital for coronary angiography within 3 months. Despite some gross similarities in the aspect of the coronary tree, the coronary dominance pattern was not the same in these twins, but coronary lesions involved almost the same sites. Genetically determined local factors, such as the rheologic profile in some sections of the coronary tree, or the susceptibility to lipid deposition in some spots, may be important in the development of atheromatous lesions in special sites.

Unsuspected infrahepatic interruption of inferior vena cava associated with floppy mitral valve, mitral valve prolapse, and severe mitral regurgitation

We describe a case of unsuspected infrahepatic interruption of the inferior vena cava with hemiazygos continuation in a 67-year-old man presenting with chest pain and evidence of mitral regurgitation. He had no persistent superior vena cava, with the hemiazygos draining directly into the right superior vena cava. Polysplenia and severe mitral prolapse were also present: the latter may represent more than an incidental finding in this condition. This malformation may deserve consideration in adults undergoing femoral right heart catheterization. Chest radiographic studies are the basic clue to the diagnosis.

[Quality assurance and cost control in invasive and interventional cardiology]

We report our experience of Quality Assurance in a Cardiac Catheterization Laboratory of the National Health Service. An attempt was made to apply these criteria to the medical activities as well as to the management and economic aspects of our work. Limits and perspectives of this experience are discussed as a contribution to ongoing debate among cardiologists and public health Authorities.

[Elective coronary angioplasty in total absence of heart surgery]

BACKGROUND

One-hundred consecutive procedures of elective coronary angioplasty were attempted in 95 patients, in the absence of any surgical stand-by. All patients had angina and/or signs of inducible ischemia.

METHODS

All patients and attending physicians were informed that no surgical coverage was available, and gave their consent. The choice was made on the basis of the estimate, on clinical and angiographic grounds, of the consequences of vessel occlusion, of the possible help offered by percutaneous bail-out techniques, and of the applicability of surgical stand-by.

RESULTS

A primary success was achieved in 92 cases: in 5 cases a Palmaz-Schatz stent was implanted. In 6 cases the procedure was unsuccessful, with no complications. Two patients sustained a myocardial infarction without new Q-waves. No patient died, nor underwent cardiac surgery within 1 month of discharge.

CONCLUSIONS

Our initial experience suggests that, in the absence of surgical stand-by, elective coronary angioplasty can be performed in selected patients at an acceptable risk.

[Invasive cardiological diagnosis in an ambulatory regimen of transported inpatients]

We report our initial experience with 302 consecutive cases of percutaneous cardiac catheterization in in-patients from other hospitals. The patients reached our laboratory immediately before the procedure in an ambulance with an attending physician and were transported back to their hospital soon after completion of the procedure. This accounts for 35% of 864 diagnostic cardiac catheterization procedures in our laboratory in the first 12 months of activity. There were no complications related to this regimen, and a substantial reduction in unnecessary overnight admission to the cardiology ward was achieved. This report confirms the safety and the advantages of this practice. Implications for the organization of the catheterization laboratory are discussed.

On-line quantitative coronary analysis in clinical practice: one step closer to reality?

Quantitative coronary analysis is widely used in studies of progression/regression and restenosis of coronary lesions. On-line digital systems are used in diagnostic coronary angiography, and as a guide in coronary interventions. The aim of this investigation was to test the reliability of measures obtained with one commercially available on-line equipment. Well-visualized coronary lesions from patient studies were analyzed for variability in single-frame measurement. Procedural factors affecting the consistency of measurements were identified by repeated visualization of the same coronary lesion with hand- and power-injection of contrast in various positions in the field of the image intensifier, and by imaging of steel phantoms in the same positions. Steel phantoms closely resembling coronary lesions as encountered in practice were visualized in the most favourable radiologic setting compatible with clinical situations. Accuracy and precision of measurements were found to be worse than reported in validation studies. This may be due to a host of variables which may need to be tested in each laboratory performing on-line quantitative coronary angiography, when data so obtained are to be used in clinical decision making or in research studies.

[Diagnostic hemodynamics in day-hospital care]

Our initial experience with 180 consecutive cases of transfemoral cardiac catheterization in ambulatory patients is presented. It accounts for 21% of 864 diagnostic cardiac catheterization procedures in our laboratory in the first 12 months of activity. There were no complications. Patient satisfaction was high, and a substantial reduction of unnecessary overnight admissions in the cardiology ward could be achieved. This confirms the safety and the advantages of this practice. Implications for the organization of the Catheterization Laboratory are also discussed, as well as possible causes for the sofar limited use of ambulatory cardiac catheterization in our country.