Co-expression of fibulin-5 and VEGF165 increases long-term patency of synthetic vascular grafts seeded with autologous endothelial cells

Small caliber synthetic vascular grafts are commonly used for bypass surgery and dialysis access sites but have high failure rates because of neointima formation and thrombosis. Seeding synthetic grafts with endothelial cells (ECs) provides a biocompatible surface that may prevent graft failure. However, EC detachment following exposure to blood flow still remains a major obstacle in the development of biosynthetic grafts. We tested the hypothesis that induced expression by the seeded EC, of vascular endothelial growth factor165 (VEGF165) and of fibulin-5, an extracellular matrix glycoprotein that has a crucial role in elastin fiber organization and increase EC adherence to surfaces, may improve long-term graft patency. Autologous ECs were isolated from venous segments, and were transduced with retroviral vectors expressing fibulin-5 and VEGF165. The modified cells were seeded on expanded polytetrafluoroethylene (ePTFE) grafts and implanted in a large animal model. Three months after transplantation, all grafts seeded with modified EC were patent on a selective angiography, whereas only a third of the control grafts were patent. Similar results were shown at 6 months. Thus, seeding ePTFE vascular grafts with genetically modified EC improved long-term small caliber graft patency. The biosynthetic grafts may provide a novel therapeutic modality for patients with peripheral vascular disease and patients requiring vascular access for hemodialysis.

Fibulin-5 regulates keloid-derived fibroblast-like cells through integrin beta-1

OBJECTIVE

Keloid scar is pathological tissue that appears after skin injury, and that is more aggressive than hypertrophic scars. Keloid scars are characterized by increased proliferation of fibroblast-like cells (FLCs) and the accumulation of extracellular matrix, mainly collagen. Fibulin-5, a glycoprotein secreted by many cell types, is a component of the extracellular matrix. We investigated the effect of fibulin-5 on the adhesion and proliferation of FLCs derived from keloid scars and the role of integrin beta-1 in these activities.

METHODS

Fibroblast-like cells were isolated from six keloid scars and cultured on plates coated with fibulin-5 or with gelatin. Cells were incubated for 72-96 h to examine proliferation rates and incubated for 240 min, with washings at 20, 40, 60, 90, 120, 180 min, to assess adhesion rates. To examine the role of integrin beta-1, the anti-human integrin beta-1 (CD29) antibody was added to the culture medium.

RESULTS

Fibroblast-like cells from keloids cultured on a fibulin-5-coated surface showed a significantly reduced proliferation rate and a delayed adhesion rate, compared to cells cultured on gelatin-coated dishes. Adherence of these cells to fibulin-5 pre-coated wells was significantly reduced in the presence of anti-human integrin beta-1 (CD29) antibodies. Our current findings are similar to previously observed reduced proliferation in vascular smooth muscle cells overexpressing fibulin-5. We did not test the effects of fibulin-5 on normal fibroblasts.

CONCLUSION

This study demonstrates the pivotal role of the extracellular protein, fibulin-5, on the adhesion and proliferation of human keloid-derived cells, through binding to integrin beta-1.

High frequency of vitamin B12 deficiency in asymptomatic individuals homozygous to MTHFR C677T mutation is associated with endothelial dysfunction and homocysteinemia

The aim of this study was to examine the association of homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and vitamin B12 deficiency in 360 asymptomatic individuals and to investigate forearm endothelial function in C677T homozygotes. MTHFR C677T mutation and levels of vitamin B12, folic acid, and homocysteine were measured in study participants. Frequency of homozygosity for the C677T mutation was 67/360 (18.6%). Homocysteine levels were elevated in homozygous compared with heterozygous subjects or those without the mutation (20.6 +/- 18.8 vs. 9.4 +/- 3.2 mumol/l; P < 0.0001). The number of subjects with vitamin B12 deficiency (<150 pmol/l) was significantly higher among the homozygote than the heterozygote subjects or subjects without mutation [20/67 (29.8%) vs. 27/293 (9.2%); P < 0.0001]. Homozygote subjects had 4.2 times higher probability of having B12 deficiency (95% confidence interval = 2.1-8.3). Forearm endothelial function was assessed in 33 homozygote and 12 control subjects. Abnormal endothelial function was observed in homozygous subjects and was worse in homozygote subjects with vitamin B12 deficiency. Endothelial function was normalized after B12 and folic acid treatment. We found that homozygosity for the C677T mutation is strongly associated with B12 deficiency. Coexistence of homozygosity for the C677T mutation and B12 deficiency is associated with endothelial dysfunction and can be corrected with vitamin B12 and folic acid treatment.

Effects of fibulin-5 on attachment, adhesion, and proliferation of primary human endothelial cells

BACKGROUND

Fibulin-5 is a novel extracellular protein that is thought to act as a bridging peptide between elastin fibers and cell surface integrins in blood vessel wall. Fibulin-5 binding to endothelial cell (EC) surface integrins may effect cell proliferation and cell attachment to extracellular matrix (ECM) or to artificial surfaces. In this paper, we describe the effects of fibulin-5 on attachment, adhesion, and proliferation of primary human EC. After demonstrating that fibulin-5 over-expression inhibited EC proliferation, we tested the hypothesis that co-expression of fibulin-5 and VEGF165 will lead to unique EC phenotype that will exhibit increased adherence properties and retain its proliferation capacity.

METHODS AND RESULTS

Fibulin-5 and VEGF165 gene transfer to primary human saphenous vein endothelial cells was accomplished using retroviral vectors encoding the two genes. Transgene expression was verified using immunohistochemistry, Western blotting, and ELISA. Fibulin 5 over-expression tended to improve immediate EC attachment (30 min after seeding) and improved significantly adhesion (>40%) under shear stress tested 24h after EC seeding. The effects of fibulin-5 and VEGF165 on EC proliferation in the presence or absence of basic FGF were also tested. EC expressing fibulin-5 had reduced proliferation while VEGF165 co-expression ameliorated this effect.

CONCLUSION

Fibulin-5 improved EC attachment to artificial surfaces. Dual transfer of fibulin-5 and VEGF165 resulted in EC phenotype with increased adhesion and improved proliferation. This unique EC phenotype can be useful for tissue engineering on endovascular prostheses.

Increased vascular endothelial growth factor 165 binding to kinase insert domain-containing receptor after infection of human endothelial cells by recombinant adenovirus encoding the Vegf(165) gene

BACKGROUND

The angiogenic effect of vascular endothelial growth factor (VEGF(165)) is mediated mainly through the high-affinity tyrosine kinase receptor VEGF-R2 (KDR/flk-1). This study examined the effects of VEGF overexpression by primary human endothelial cells (ECs), which do not express VEGF under physiological conditions, on cell proliferation, VEGF binding to the kinase insert domain-containing receptor (KDR), and KDR expression.

METHODS AND RESULTS

Human primary ECs and SMCs were infected by recombinant adenoviral vector encoding VEGF(165) (rAdVEGF). Proliferation rate, bromodeoxyuridine incorporation, (125)I-labeled VEGF(165) binding to the KDR receptor, and KDR expression were tested in the infected cells and in cells supplemented with VEGF protein. Enhanced proliferation and a significant increase in (125)I-VEGF(165) binding to the KDR receptor were induced by rAdVEGF infection of ECs (autocrine effect) as well as by addition of recombinant VEGF(165) to noninfected cells. Infection of ECs by rAdVEGF led to posttranscriptional upregulation of the KDR receptor, whereas KDR mRNA expression levels remained unchanged. Similar effects were observed with supplemented recombinant VEGF(165) to noninfected ECs; nevertheless, this phenomenon occurred only with high VEGF(165) concentrations (10 ng/mL).

CONCLUSIONS

The effect of VEGF(165) on proliferation and upregulation of KDR receptor expression demonstrated an autocrine phenomenon of EC sensitization. The fact that high concentrations of VEGF may be achieved in vivo by local continuous overexpression of VEGF(165) by gene transfer emphasizes the potential advantage of gene transfer over protein supplementation for therapeutic angiogenesis.

Perceived benefit after participating in positive or negative/neutral heart failure trials: the patients' perspective

BACKGROUND

Clinical trials, the gold standard for the evaluation of new therapeutic strategies, may prove a drug to be beneficial, harmful or neutral according to its effect on the end-point(s) under study.

AIMS

To study the reaction and perspective of the patients participating in a clinical heart failure trial, particularly in relation to whether the trial subsequently proved to be positive, negative or neutral.

METHODS

Anonymous self-completed questionnaire was sent to 78 and returned by 70 consecutive patients 1--6 months after participating in six clinical heart failure trials. The trial was neutral or negative regarding the primary end-point in four (47 patients) of the six studies (MACH-1 trial of mibefradil, REACH trial of bosentan, CASCO trial of calcium sensitizer, ecadotril trial of neutral endopeptidase inhibitor) and positive in two (23 patients) (ICARUS Israel carvedilol study, exercise study of candesartan cilexetil).

RESULTS

Most patients reported subjective global clinical benefit (78% for positive, 74% for negative or neutral trial, NS) after participating in a clinical trial. After adjustment for age, sex, level of education, previous research, perceived comprehension, and treatment allocation (active drug/placebo) in a stepwise regression model, perceived global improvement was greater in older patients (P=0.02), after participation in a positive trial (P=0.05) and in females (P=0.07). The major reason given by the patient for perceived clinical improvement was better follow-up, some believed it was due to change in medication, particularly those who had participated in a positive trial.

CONCLUSIONS

More than 70% of patients participating in clinical trials of new drugs for heart failure reported perceived global improvement. Clinical improvement was greater in, but not limited to, patients who participated in positive trials. These salutary findings support the continued recruitment of patients to clinical heart failure trials.

Similar late revascularization rates 10 to 12 years after angioplasty or bypass surgery for multivessel coronary artery disease: a report from the Lady Davis Carmel Medical Center (LDCMC) Registry

We compared completed long-term outcome and late repeat revascularization rates in 272 consecutive patients with multivessel coronary disease who underwent revascularization (95 angioplasty cohort, 177 surgical cohort) between 1984 and 1986. Long-term survival was similar at 12 years in the angioplasty (70%) and surgical (74%) cohorts (p = NS), and repeat revascularization, although more frequent in the angioplasty patients during the first 5 years of follow-up, was performed equally in the 2 patient cohorts after 10 to 12 years of follow-up.

Therapeutic angiogenesis for ischemic syndromes

Disease caused by atherosclerosis are the most common causes of morbidity and mortality in western societies. The inadequacy of current therapeutic modalities is most pronounced in the significant proportion of patients with arterial obstructive disease, in whom anatomical and technical limitations rule out the possibility of angioplasty or surgery. Therefore, less invasive approaches are necessary to treat these patients. The development of collateral circulation improves blood flow to ischemic tissues and to alleviate ischemia-related symptoms. Our project concentrates on enhancement of the natural mechanism of angiogenesis by adenoviral based vector encoding vascular endothelial growth factor as an angiogenic factor. The aim of our study was to determine the efficacy of human vascular cell infection by adenoviral based vectors in vitro and in vivo. Human saphenous vein endothelial cells and smooth muscle cells were infected by adenoviral vectors encoding the lacZ and VEGF genes (rAdlacZ, rAdVEGF). VEGF expression by adenoviral vector-infected cells was detected by western analysis and its biological activity was examined by proliferation assay. The feasibility of adenoviral based gene transfer in vivo was evaluated after direct femoral artery injection of rAdlacZ in the rat. Vascular endothelial and smooth muscle cells expressed high levels of VEGF following rAdVEGF infection. The mitogenic effect of VEGF was validated by threefold increase in EC proliferation rate in comparison to the control groups. In vivo gene transfer was demonstrated using lacZ gene transfer to arterial wall cells in the superficial femoral artery. Efficient adenoviral based gene delivery was demonstrated both in vitro and in vivo. VEGF over-expression enhanced endothelial cell proliferation, which is the key step for induction of angiogenesis.

Late-onset heart failure as a mechanism for adverse long-term outcome in diabetic patients undergoing revascularization (a 13-year report from the Lady Davis Carmel Medical Center registry)

The adverse long-term prognosis following myocardial revascularization in diabetic patients has been ascribed to accelerated coronary disease, a higher incidence of late coronary restenosis after revascularization, and myocardial dysfunction. To examine the development of heart failure and its prognostic implications in diabetic patients, we analyzed the long-term (13-year) follow-up data of 363 patients-193 percutaneous transluminal coronary angioplasties and 170 coronary artery bypass operations-revascularized in a single cardiovascular center from 1984 to 1986. Baseline characteristics (age, previous infarction, baseline ventricular function) were similar in the 80 diabetic and 283 nondiabetic patients; multivessel disease and hypertension were marginally more common in diabetics (p = NS). Cumulative incidence of hospitalization for heart failure was high in the diabetic cohort (25% vs 11%, p = 0.001), with a rapidly increasing incidence after 5 years. Survival after first hospitalization for heart failure was markedly reduced in diabetics (11 of 20 [55%] vs 25 of 31 [81%] at 3 years; p = 0.04), as was survival free of further hospitalization for heart failure (5 of 20 [25%] vs 20 of 30 [63%]; p <0.005). Long-term 13-year survival (43% vs 78%, p <0.0001) and survival free of heart failure (33% vs 71%, p <0.0001) were decreased in diabetics, especially those with reduced ventricular function at baseline (17% vs 42%, p = 0.07). Multivariate analysis showed diabetes to be the strongest independent predictor of decreased survival (odds ratio 3. 6, 95% confidence interval 2.0 to 6.2; p <0.0001) and survival free of heart failure (odds ratio 4.0, 95% confidence interval 2.2 to 7. 1; p <0.0001) in patients undergoing revascularization. In summary, late-onset heart failure was frequent in diabetic patients after percutaneous transluminal coronary angioplasty or coronary artery bypass grafting, and once present heralded an unrelenting progressive downhill clinical course.

Same-day combined coronary angioplasty and minimally invasive coronary surgery

Integrated myocardial revascularization combines the advantages of angioplasty, stenting, and minimally invasive surgery to revascularize patients with multivessel coronary artery disease without cardiopulmonary bypass. This pilot study showed that a new same-day management strategy, consisting of percutaneous coronary intervention followed immediately by minimally invasive surgery, was feasible and provided complete all-arterial revascularization with minimal surgical trauma, short hospital stay, and excellent early therapeutic result in 14 patients with multivessel coronary disease.

Long-term (10-year) outcome in patients with unstable angina pectoris treated by coronary balloon angioplasty

OBJECTIVES

We sought to examine completed 10-year survival and event-free survival in patients with stable and unstable angina pectoris treated by coronary balloon angioplasty.

BACKGROUND

Patients with unstable angina are at increased risk for recurrent acute coronary events.

METHODS

The study included 208 consecutive patients (133 with stable and 75 with unstable angina pectoris) undergoing angioplasty from 1984 to 1986. The balloon crossed the lesion in 185 patients (121 with stable and 64 with unstable angina pectoris). Angioplasty was performed in patients with unstable angina pectoris 12+/-15 days (median 8) after symptom onset. Patients with unstable angina pectoris were classified retrospectively into Braunwald class I (n=3), class II (n=20), class III (n=28), class B (n=52) and class C (n=12). Follow-up data were obtained from hospital charts, telephone interview and official death certificates where applicable. The study had >80% power to detect a clinically significant 20% difference in survival and a 20% difference in event-free survival between the stable and unstable patient groups.

RESULTS

Despite similar baseline characteristics, early (40-day) mortality was slightly higher in patients with unstable angina (4.7% [3 of 64 patients] vs. 0.8% [1 of 121 patients], p=NS). Long-term outcome was not different, because survival curves were parallel thereafter (10-year survival was 83% for those with stable and 77% for those with unstable angina, p=NS). Survival free of myocardial infarction or coronary artery bypass graft surgery at 10 years was 53% in patients with stable and 47% in patients with unstable angina (p=NS), and survival free of infarction, bypass surgery or repeat angioplasty was 32% for both groups at 10 years. In patients with Braunwald class III unstable angina, 10-year survival was 80%, as compared with 85% in other patients with unstable angina, due to the early hazard (p=NS). Survival and event-free survival were similar in patients who had had a recent myocardial infarction (Braunwald class C) and in patients with acute electrocardiographic changes. Repeat hospital admissions were not more frequent in patients with unstable angina (3.1+/-3.5 vs. 3.0+/-2.6, p=NS).

CONCLUSIONS

Ten-year survival and event-free survival were similar in patients with stable and unstable angina pectoris treated by coronary balloon angioplasty, with no evidence of an increased rate of recurrent cardiovascular events in the unstable group.

Importance of diabetes mellitus and systemic hypertension rather than completeness of revascularization in determining long-term outcome after coronary balloon angioplasty (the LDCMC registry). Lady Davis Carmel Medical Center

The study examined the 10-year outcome in a cohort of 227 unselected, consecutive patients (age 58+/-10 years) undergoing coronary balloon angioplasty between 1984 and 1986 and followed in a single cardiac center (Lady Davis Carmel Medical Center registry). In particular, we sought to identify the relative importance of the systemic risk factors diabetes and hypertension and the extent of coronary disease as opposed to procedure-related technical variables, the immediate success of the procedure, or completeness of revascularization. By life-table analysis (99% follow-up), 94% of the patients were alive at 5 years, and 77% at 10 years after angioplasty. Ten-year survival was reduced in patients with diabetes mellitus (59% vs 83%, p = 0.0008), in patients with previous myocardial infarction (68% vs 85%, p = 0.01), in patients with ejection fraction <50% (55% vs 82%, p = 0.005), and in patients with 3-vessel disease (58% vs 84% and 86% for 1- and 2-vessel disease, respectively, p = 0.04). Diabetes mellitus was the major independent predictor of poor survival (adjusted odds ratio 3.1, 95% confidence interval 1.55 to 6.19, p = 0.001). Survival at 10 years was identical in 199 patients in whom angioplasty was complete and in 25 in whom the balloon catheter did not cross the lesion, although bypass surgery was more frequent in the latter group (45% vs 21%, p = 0.001). Incomplete revascularization did not predict poor survival (72% vs 79% with complete angioplasty, p = NS). Event-free survival at 10 years for the whole group was 29%, and 49% of patients survived with no event other than a single repeat angioplasty procedure. Multivessel disease, hypertension, and diabetes mellitus were independent predictors of decreased event-free survival, but incomplete revascularization was not. Thus, long-term outcome after coronary balloon angioplasty was related to diabetes mellitus, systemic hypertension, and extent of coronary disease, but not to the immediate success of the procedure or completeness of revascularization.

Ventricular remodeling: from bedside to molecule

The multiple mechanisms that bring about the decompensation of the hypertrophic remodeled myocardium are synergistic and not fully understood. Our current hypothesis is that the increased stress on the ventricle is initially offset by compensatory myocardial hypertrophy. In many instances, however, progressive ventricular dilatation and heart failure occur as a result of maladaptive hypertrophy (abnormal myosin-actin production), programmed cell death (apoptosis) and/or changes in the interstitial vasculature and collagen composition. The molecular and genetic background to these processes includes changes in myocardial gene expression, activation of the local tissue renin-angiotensin and other neurohormonal systems, increased matrix metalloproteinase activity (including collagenase), and expression of certain components of the immune system, such as TNF-alpha. Future research will hopefully provide better methods for limiting the remodeling-ventricular dilatation process by novel pharmacotherapies, gene therapy and, possibly, surgical therapy, and determine the impact of such interventions on survival.

Angiogenesis by gene therapy: a new horizon for myocardial revascularization?

The concept of therapeutic angiogenesis is based on the premise that the potential for vascular growth inherent in vascular tissue can be utilized to promote the development of new blood vessels under the influence of the appropriate growth factors. Direct application of growth factors of the fibroblast (acidic, basic fibroblast growth factor, FGF-5), endothelial (vascular endothelial growth factor) and other series has been effective in preliminary studies. Angiogenesis by gene transfer provides an attractive alternative, with the advantage that the protein may continue to be secreted for a longer period of time and that the gene may be targeted to specific tissues to enhance efficacy and reduce systemic side effects. Angiogenesis by gene transfer is currently under investigation using a variety of growth factors and a wide array of potential delivery systems. These include application of the gene as naked DNA or by viral vector in the proximal vessel by direct intravascular injection, interventional cardiologic techniques (hydrogel coating on balloon, double balloon system, stent implantation) or by direct application to adventitia, pericardium or ischemic tissue distal to the site of arterial obstruction. As our understanding of the molecular and genetic processes underlying angiogenesis increases, and as we examine the results of preliminary animal and human protocols, we hope to develop the potential of angiogenesis by gene transfer for therapeutic use.

Importance of immediate and very early postprocedural angiographic and thallium-201 single photon emission computed tomographic perfusion measurements in predicting late results after coronary intervention

We examined prospectively the hypothesis that the adequacy of initial dilatation may be a major determinant of the late result of coronary angioplasty and that a better assessment of initial dilatation can be made from a combined angiographic and perfusion study than from angiography alone. Angiographic and perfusion (thallium-201 single-photon-emission computed tomography) measurements were made very early (18 to 24 hours) after coronary angioplasty in 59 patients (67 lesions) and also immediately (37 +/- 16 minutes) after the procedures in 19 of them (23 lesions). The early measurements, singly, in combination, and as a restenosis index (restenosis index = thallium-201 ischemic score (units) - minimal luminal area (squared millimeters) were examined as predictors of the late angiographic result. At late angiography (5.5 +/- 2.2 months after angioplasty), residual stenosis was related to the immediate and very early postangioplasty minimal luminal dimension, thallium-201 ischemic score, and restenosis index, and also to day-1 loss and lesion length. The combination of a normal result in the immediate or early thallium-201 perfusion study with a large ( > or = 2 mm) angiographic luminal dimension stratified a group of patients with better long-term results after angioplasty and a lower incidence of late restenosis (p = 0.03). The findings emphasize the importance of the initial procedure as a determinant of the late result of angioplasty.

Inhibition of intravascular thrombosis and vascular smooth muscle cell proliferation by gene therapy

Intravascular thrombosis, smooth muscle cell proliferation and matrix production lead to arterial luminal narrowing and reduction of blood flow to various organs. Alteration of gene expression of the arterial wall cells to inhibit thrombosis and smooth muscle activation is emerging as a new and exciting therapeutic modality for cardiovascular pathology. We have used genetically modified endothelial cells to seed endovascular prostheses and tested cell adhesion to the prostheses both in vitro and in vivo. We also used two catheter-based systems to deliver genes directly to the arterial wall cells in vivo employing retroviral and adenoviral vectors. With efficient vectors for gene transfer and high level expression of proteins by the transduced cells, gene therapy will serve as a major therapy for post-angioplasty restenosis, unstable angina pectoris and vascular grafts stenosis.

Vascular gene therapy

Gene therapy is emerging as a new and exciting therapeutic modality for cardiovascular pathology. The work reported here was carried out in the National Heart, Lung and Blood Institute (NHLBI) in Bethesda, MD, USA, where genetically engineered endothelial cells were used to seed endovascular prostheses and cell adhesion to the prostheses was tested both in vitro and in vivo. Two catheter based systems were used to deliver genes to the arterial wall cells in vivo, employing retroviral and adenoviral vectors. Efficient gene transfer to vascular cells in vivo was achieved with adenoviral vectors.

Usefulness of late potentials on the immediate postoperative signal-averaged electrocardiogram in predicting ventricular tachyarrhythmias early after isolated coronary artery bypass grafting

The present study was undertaken to determine the value of abnormal late ventricular potentials on signal-averaged electrocardiograms (ECG) in identifying patients at risk of developing ventricular tachycardia or ventricular fibrillation in the early postoperative period after coronary artery bypass grafting. Signal-averaged ECGs were recorded immediately after operation in 72 patients. Abnormal late potentials were defined as the presence of 2 or 3 of the following: (1) root-mean-square amplitude of the last 40 ms of the QRS < 20 microV; (2) duration of the terminal QRS potentials (after 40 microV) > or = 39 ms; and (3) high-frequency QRS duration > 120 ms (in patients with conduction defects, only the first 2 criteria were used). Abnormal late ventricular potentials were present on the immediate postoperative signal-averaged ECG in 26 of the 72 patients (36%). Life-threatening ventricular tachyarrhythmias occurred in 6 patients. Late potentials were present in all 6 patients, but only in 20 of 66 (30%) who did not develop ventricular tachyarrhythmias (p < 0.005) (sensitivity 100%, specificity 70%, predictive accuracy 72%). Of 12 pre- and perioperative variables examined by univariate and multivariate regression analysis, the presence of late potentials on the signal-averaged ECG and low cardiac output postoperatively were found to be independent predictors of life-threatening tachyarrhythmias.

Anatomic barriers influence the distribution of in vivo gene transfer into the arterial wall. Modeling with microscopic tracer particles and verification with a recombinant adenoviral vector

We evaluated the extent to which anatomic barriers to vector penetration might influence the distribution of successful in vivo gene transfer into the normal arterial wall. A double-balloon catheter technique with infusion pressures of 100 to 400 mm Hg was used to infuse microscopic tracer particles of the size range of liposomes and viral vectors into normal elastic arteries of sheep. Localization of the tracer particles in tissue sections by light, fluorescence, and electron microscopy suggested that vector-sized particles were delivered to the intima by direct infusion and to the adventitia via the arterial vasa vasorum. Particles were virtually absent from the arterial media. To test the predictions made from the particle studies, we repeated the infusion protocol with high-titer adenoviral vectors. Gene transfer occurred at high levels in the intima and along the adventitial vasa vasorum but again was virtually absent within the media. The ability of medial smooth muscle cells to be transduced was established in separate experiments with a high-pressure (5 atm) porous balloon infusion catheter. We conclude that (1) the anatomy of the normal elastic arterial wall imposes significant limitations on the penetration of particles in the size range of most gene-transfer vectors and (2) the distribution of in vivo gene transfer with adenoviral vectors is correctly predicted by the distribution of inert tracer particles. These findings have important implications for the design of arterial gene-transfer and gene-therapy protocols.

Smooth muscle cell abundance and fibroblast growth factors in coronary lesions of patients with nonfatal unstable angina. A clue to the mechanism of transformation from the stable to the unstable clinical state

BACKGROUND

The mechanisms responsible for the transformation of stable angina to unstable angina, a major cause of morbidity and mortality, are commonly believed to be plaque rupture and thrombosis. We determined whether additional mechanisms are operative by analyzing the histopathology and immuno-histopathology of coronary plaques retrieved by directional atherectomy of patients with unstable angina in whom no intraluminal thrombus was demonstrated by angiography.

METHODS AND RESULTS

The histological findings of atherectomy specimens from 34 patients with unstable angina were compared with those of 24 patients with postangioplasty restenosis, whose lesions are known to be composed of smooth muscle cells (SMCs), and 10 patients with stable angina, whose lesions contain relatively few SMCs. We also studied the expression of acidic and basic fibroblast growth factors (aFGF and bFGF), whose role in the vascular response to injury has been established. Specimens from unstable angina resembled those from postangioplasty restenosis in regard to SMC abundance (scale, 0 to 3; 1.4 +/- 0.9 versus 1.7 +/- 0.9; P = NS), and both differed from those of stable angina. Thrombus and/or hemorrhage occurred in only 34% of patients with unstable angina (compared with 8% of restenosis patients and in none of stable angina patients). Active lesions (defined as lesions (defined as lesions containing one or more of the following: thrombus, hemorrhage, abundant and disorganized SMCs in the presence of loose connective tissue, or inflammatory infiltrate) were observed in 56% of the unstable angina patients and in 50% of the restenosis patients but in none of the stable angina patients. The expression of aFGF and bFGF was detected in 80% to 100% of unstable angina (n = 11) and restenosis (n = 10) specimens but in only 1 of 5 stable angina specimens.

CONCLUSIONS

Microscopic evidence of thrombosis and plaque rupture occurred in only one third of unstable angina patients, selected because they had no angiographic evidence of intracoronary thrombus. Moreover, their lesions resembled those of restenosis patients in regard to SMC abundance, lesion activity, and the expression of aFGF and bFGF. Our findings therefore suggest that an alternative mechanism to plaque rupture and thrombus formation may be operative in the precipitation of unstable angina; namely, in a subset of patients, SMC proliferation may lead to gradual plaque expansion and thereby to lumenal narrowing and unstable angina. Our data also suggest a role for aFGF and bFGF in this process.

Atrial natriuretic peptide in severe heart failure: response to controlled changes in atrial pressures during intravenous nitroglycerin therapy

Atrial natriuretic peptide (ANP) levels were measured in 17 patients with severe congestive heart failure (New York Heart Association functional class IV), and the response of the peptide was studied during changes in cardiac filling pressures induced by a 24-hour infusion of nitroglycerin. In the control state plasma ANP levels (687 +/- 551 pg/ml) were 10-fold normal. During the administration of nitroglycerin, natriuretic peptide levels decreased (p less than 0.005) with changes matching very closely the decreases in pulmonary arterial wedge and right atrial pressures, a 1% mean decrease in the peptide level for every 1.5 to 2% mean change in atrial filling pressures. In patients with hemodynamic tolerance to constant-dose nitroglycerin infusion, the resulting increase in atrial pressures was accompanied by an appropriate secondary increase in the plasma ANP level. During the 24-hour study period there was a direct linear relationship between both wedge (r = 0.93, p = 0.007) and right atrial (r = 0.93, p = 0.008) pressures and the plasma ANP level, with a zero-pressure ANP intercept near normal (69 pg/ml for wedge, 174 pg/ml for right atrial pressure). The findings were no different in a subgroup of five patients receiving simultaneous treatment with captopril, except that plasma renin activity was higher and the aldosterone level lower than in the control group by a factor of approximately 2.5. The close relationship and tracking of atrial pressure and natriuretic peptide curves suggested that the sensitivity of the atrial stretch response to changes in atrial filling pressures was maintained in severe congestive heart failure.

Low level in vivo gene transfer into the arterial wall through a perforated balloon catheter

BACKGROUND

Gene transfer into the arterial wall may provide a novel therapeutic strategy for the treatment of coronary artery restenosis. Previously described methods for gene transfer into the arterial wall require total vessel occlusion for 30 minutes. We sought to develop a protocol for gene transfer within a more clinically relevant time frame.

METHODS AND RESULTS

We used a perforated balloon (Wolinsky) catheter to inject retroviral vector-containing virions into rabbit aortas in vivo. The virions were injected within 1 minute. Aortas were removed 5-14 days after injection and analyzed for evidence of gene transfer. In initial studies, nine rabbits were injected with a vector expressing the beta-galactosidase gene, and nine rabbits were injected with either non-beta-galactosidase-containing vectors or with a vehicle control. Histochemical staining of aortic tissues revealed blue (positive) cells in eight of nine experimental rabbits and six of nine controls. Because of the lack of specificity of the beta-galactosidase detection system, we adopted a polymerase chain reaction-based protocol in which oligonucleotide primers were used to amplify specific vector-related sequences from aortic tissue extracts. The polymerase chain reaction protocol, calibrated with standards containing known numbers of transduced cells, revealed low amounts of vector-related sequences in six of 12 vector-injected rabbits and in one of 13 controls (p less than 0.03). Comparison with standards indicated that fewer than 100 transduced cells were present in a 2-cm length of the injected aortic tissue.

CONCLUSIONS

Although in vivo gene transfer through an infusion balloon catheter can be accomplished within 1 minute, the therapeutic use of this protocol is limited by the small number of cells that are transduced.

Genetically engineered endothelial cells remain adherent and viable after stent deployment and exposure to flow in vitro

Intravascular stents, currently in experimental human use for recurrent arterial stenosis, are plagued by subacute thrombosis. As a therapeutic approach to stent-related thrombosis, we and others have suggested coating stents with endothelial cells before implantation. In a previous study we demonstrated the feasibility of coating stents with endothelial cells that were genetically modified to secrete large amounts of human tissue plasminogen activator. In the present study we attempted both to develop a clinically applicable protocol for stent seeding and to test whether seeded cells would remain adherent to stents after exposure to pulsatile flow. Endothelial cells were harvested from the saphenous veins of sheep with survival of the donor animals. Harvested cells were transduced with a retroviral vector containing a marker gene and seeded onto catheter-mounted stents under sterile conditions. Scanning electron microscopy revealed complete coverage of the stent surfaces by seeded cells. Stents were expanded and exposed to pulsatile flow in vitro. Substantial cell retention was observed on the lateral stent surfaces by light microscopy and scanning electron microscopy; fewer cells were seen on the luminal and abluminal surfaces. Removal of seeded cells from flow-exposed stents by trypsin digestion resulted in the recovery of approximately 70% of the seeded cells. These cells were viable and healthy as judged by their ability to proliferate to confluence with the same kinetics as control (non-flow-exposed) cells. Autologous genetically modified endothelial cells can be seeded onto catheter-mounted stents in a sterile manner, and stent deployment under flow conditions results in substantial retention of viable cells.

Clinical, psychological and thallium stress studies in patients with chest pain and normal coronary arteries

The clinical and psychological profiles of 36 consecutive patients with chest pain and normal coronary arteries (study group) were compared to those of 34 patients with chest pain and significant coronary arterial disease (control group). All 70 patients were hospitalized for chest pain at least once prior to coronary angiography. The features of a typical episode of chest pain were similar in the normal coronary arteries and coronary arterial disease groups, but the female patients with normal coronary arteries had a shorter duration of a typical episode of chest pain, and the male patients with normal coronary arteries had a lower frequency of positive effort tests. Psychological testing showed the women with normal coronary arteries to have a tendency to increased somatization, anxiety, and a lower ability to identify origin of difficulties. The patients in the normal coronary and coronary arterial disease groups had psychological profiles typical of patients with chronic somatic disease. A psychiatric interview demonstrated an increased frequency of depressive trait (score 0-2) in the normal women (0.6 +/- 0.8 vs 0, P less than 0.05), and a tendency to increased somatization, anxiety, and sleeping disorders. Increased somatization was found in the normal coronary men (1.1 +/- 0.7 vs 0.5 +/- 0.7, P less than 0.05). Twenty-five patients of the normal coronary group underwent quantitative thallium stress studies, and 13 patients (52%) had evidence of stress-induced myocardial perfusion defect. There were no differences in the clinical and psychological profiles of the patients with normal and those with pathological thallium stress tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of long-term digitalization to prevent rapid ventricular response in patients with paroxysmal atrial fibrillation

Digitalis is frequently prescribed to patients with paroxysmal atrial fibrillation to reduce the ventricular rate during subsequent paroxysms. To verify the validity of this assumption, we determined the ventricular rate during paroxysmal atrial fibrillation in 13 patients receiving long-term digoxin therapy (mean plasma digoxin level + 1.28 +/- 0.4 ng/ml) and compared it with that of a group of 14 patients who had not taken digoxin or beta-adrenergic and calcium-blocking agents before the attack. The treated and the untreated groups were similar statistically. The mean ventricular rate of the digitalized patients was 121 +/- 15 beats per minute, while that of the patients in the control group was 118 +/- 16 beats per minute. It is concluded that long-term digoxin therapy is not effective in reducing the ventricular response in patients with paroxysmal atrial fibrillation despite adequate therapeutic levels.

Effect of nisoldipine on exercise performance in heart failure following myocardial infarction

The effects of the second generation calcium channel blocking drug nisoldipine on subjective and objective measurements of exercise performance were studied in 19 patients with moderate to severe heart failure (9 New York Heart Association functional class 2, 9 class 3 and 1 class 4) due to fixed ventricular dysfunction following myocardial infarction. Nisoldipine (10 mg 3 times daily) or placebo were administered for 8 weeks in a double-blind parallel study, assessing exercise performance by symptom-limited treadmill exercise testing using a modified Naughton protocol. Nisoldipine was well-tolerated and produced a small increase in peak estimated workload performed (6.2 +/- 2.9 to 8.2 +/- 3.0 METs, p = 0.06). The rate of perceived exertion (Borg scale) increased from 17.5 +/- 2.2 to 18.8 +/- 1.2 (p less than 0.02). The higher workload was performed at a lower peak systolic blood pressure (p = 0.03), higher peak heart rate (p = 0.06) and identical double product (NS). There was no change in resting and peak heart rate and blood pressure or in exercise performance in patients receiving placebo. Resting left ventricular ejection fraction, measured by radionuclide ventriculography, was unchanged after 8 weeks both in the placebo (21 +/- 9 to 20 +/- 9%) and nisoldipine (34 +/- 17 to 36 +/- 19%) groups.

Failure of captopril to prevent nitrate tolerance in congestive heart failure secondary to coronary artery disease

The possible role of angiotensin-converting enzyme inhibition in preventing or minimizing tolerance to intravenous nitroglycerin in severe congestive heart failure (CHF) was studied by quantitating the degree of tolerance in 12 patients receiving nitroglycerin (group 1) and in 9 patients (group 2) receiving nitroglycerin and concurrent treatment with captopril (60 +/- 29 mg/day). At peak effect, nitroglycerin produced almost identical hemodynamic changes in both groups, with significant decreases in right atrial and pulmonary arterial wedge pressure, systolic blood pressure and systemic and pulmonary vascular resistances. Cardiac index increased. The extent of nitrate tolerance was calculated for each hemodynamic parameter as the percentage loss of the peak effect achieved by the drug. At 24 hours, 98 +/- 80% of the benefit achieved with respect to right atrial pressure was lost in group 1 and 61 +/- 74% in group 2 (group 1 vs 2, difference not significant). For pulmonary arterial wedge pressure, 51 +/- 31% (group 1) and 85 +/- 53% (group 2) (difference not significant) of the effect was lost, and for cardiac index, 53 +/- 58% (group 1) and 54 +/- 44% (group 2) (difference not significant). Tolerance was also almost identical regarding systolic blood pressure and systemic and pulmonary vascular resistance. Thus, the extent of tolerance to high-dose intravenous nitroglycerin in CHF was unaltered by administration of captopril, indicating that in clinical dosage, counter-regulatory neurohumoral mechanisms involving the renin-angiotensin system appear to be unimportant in its development.

Nitrate tolerance in heart failure: differential venous, pulmonary and systemic arterial effects

The hemodynamic profile of tolerance to intravenous nitroglycerin was studied in 9 patients with New York Heart Association Class III to IV congestive heart failure. After rapid dosage build-up to the maximal tolerated dose (decrease in pulmonary wedge pressure to 10 mm Hg or systolic blood pressure to 90 mm Hg), nitroglycerin (525 +/- 548 micrograms/min) was administered at a constant continuous intravenous infusion for a total of 24 hours. The extent of nitrate tolerance at 24 hours was calculated as the percentage loss of the benefit achieved at time of peak effect of nitroglycerin. Tolerance had a different time course and magnitude in the venous, arterial and pulmonary circulations. At 24 hours, right atrial pressure and pulmonary vascular resistance returned to control values in most patients, while 40 to 50% of the effect on systemic vascular resistance, cardiac index and pulmonary wedge pressure was maintained. These findings emphasize the importance of precise definitions in studies relating to nitrate tolerance.

Predicting late restenosis after coronary angioplasty by very early (12 to 24 h) thallium-201 scintigraphy: implications with regard to mechanisms of late coronary restenosis

To examine whether late coronary restenosis may be predicted by abnormalities of myocardial perfusion in the early hours after successful percutaneous transluminal coronary angioplasty and to study in greater detail the mechanisms involved in the development of late coronary restenosis after angioplasty, a prospective study was undertaken in 90 consecutive patients. Thallium-201 scintigrams were recorded at rest and during the stress of atrial pacing, 12 to 24 h after angioplasty, and the results were related to the findings at angiography in 70 patients undergoing late cardiac catheterization. A reversible thallium-201 perfusion defect was found in 39 (38%) of 104 myocardial regions supplied by the dilated coronary vessel and identified a subset of patients at high risk of late (6 to 12 months) angiographic restenosis (sensitivity 77%, specificity 67%). In contrast, late coronary restenosis developed in only 7 (11%) of 65 vessels and in 5 (14%) of 37 patients with a nonischemic thallium-201 scintigram on day 1 (p less than 0.005). Multivariate logistic regression analysis of 14 possible preangioplasty and periangioplasty clinical and angiographic variables selected reversible perfusion defect on the thallium-201 scintigram on day 1 (p = 0.016) and immediate postangioplasty residual coronary narrowing (p = 0.004) as significant independent predictors of late restenosis, with younger patient age as an additional less powerful predictor (p less than 0.05). The findings have important implications regarding the pathogenesis of late coronary restenosis in patients undergoing successful angioplasty and they imply that in the majority of these patients pathophysiologic events in the early minutes and hours after angioplasty may determine the development of late restenosis.

Brucellosis in patients with heart disease: when should endocarditis be diagnosed?

Three patients, 2 with congenital valvular heart disease and 1 with a prosthetic aortic valve developed brucellosis. Brucella melitensis was isolated from blood of all 3 patients. The clinical and microbiological features suggested Brucella endocarditis and following successful antibiotic therapy, no surgery was required. The salient diagnostic features are discussed with emphasis on the management and prognosis of patients with Brucella endocarditis.

Effect of the second-generation calcium channel blocking drug nisoldipine on diastolic left ventricular dysfunction in heart failure

The effect of intravenous nisoldipine (0.12 microgram/kg/min) on diastolic left ventricular (LV) dysfunction was studied from simultaneous hemodynamic and radionuclide measurements in 12 patients with New York Heart Association class II to IV cardiac failure. The initial LV filling fraction was low, the peak LV filling rate normalized for end-diastolic volume was decreased, and the pulmonary capillary wedge pressure (PCWP) was high and associated with clinical shortness of breath. Nisoldipine produced an increase in LV filling fraction from 36 +/- 17% to 43 +/- 20% (p = 0.003). The increase in filling took place in both early and late diastole: peak early filling rate (PFR) increased in 11 of the 12 patients (p = 0.02) and late diastolic filling rate (atrial [A] wave in eight of them (NS). When the determinants of these changes, were examined further, it was found that in the control state PFR was inversely related to LV end-systolic volume (r = 0.77), whereas the A wave was related in exponential fashion to PCWP (preload) (r = 0.79). Nisoldipine did not change the slope of these relationships, and it did not alter the end-diastolic pressure-volume relationship, implying that inherent myocardial relaxation and distensibility were unaltered by the drug. In summary, nisoldipine improved measurements of diastolic LV dysfunction in patients with cardiac failure. This study illustrates the importance of considering ventricular loading conditions when analyzing and interpreting measurements of diastolic ventricular dysfunction. The measured changes in diastolic LV function during infusion of nisoldipine appear to be due to alterations in ventricular loading conditions rather than to a direct myocardial effect of the drug.

Identifying patients at high risk for restenosis after percutaneous transluminal coronary angioplasty for unstable angina pectoris

To study the determinants of late restenosis after percutaneous transluminal coronary angioplasty (PTCA) performed in patients with unstable angina pectoris, a prospective study was undertaken in 90 patients. Primary PTCA success was achieved in 84 (93%) patients, dilating 116 of 118 coronary narrowings (1.4/patient), while major complications during PTCA occurred in only 1 patient (1 death). Eighty-two patients (114 dilated arteries) were followed for 25 +/- 11 months: 68 (83%) were in New York Heart Association functional class I or II, 11 (13%) in class III, and there were 3 deaths. Late restenosis was found in 16 (25%) of 65 lesions (29% of 49 patients) studied by angiography 9 +/- 7 months after PTCA. Restenosis was more frequent in left anterior descending coronary artery lesions (p = 0.07) and in those which at the time of PTCA had multiple irregularities (67 vs 14%, odds ratio 12.5, p = 0.002), decreased coronary perfusion (Thrombolysis in Myocardial Infarction grade less than 3) (50 vs 15%, odds ratio 5.7, p = 0.02) or intraluminal thrombus (67 vs 19%, odds ratio 8.7, difference not significant). Multiple irregularities (p = 0.003) and decreased flow (p = 0.02) remained independent predictors of restenosis (goodness of fit 0.88) after adjustment for 12 pre- and peri-PTCA clinical and angiographic variables by logistic regression analysis. These data underline the feasibility of early revascularization by PTCA in patients with unstable angina pectoris. Careful follow-up should be instituted in patients with multiple irregular lesions, decreased coronary perfusion or intraluminal thrombus at the time of PTCA. In such patients, late restenosis may be the rule rather than the exception.

Hepatitis during measles in young adults: possible role of antipyretic drugs

Fifty-six per cent of 118 young adults observed during a recent measles epidemic had some disturbance on liver function tests. Five per cent developed overt jaundice. Patients treated for fever with paracetamol were found to have significantly higher rates of transaminase impairment compared to those treated with dipyrone. Sixty-five and 58% of patients given paracetamol had elevated ALT and AST levels, respectively. Only 15% of patients given dipyrone had elevated levels of these two enzymes (p less than 0.01 for ALT and p less than 0.02 for AST). The mean levels of transaminases and bilirubin in the paracetamol-treated patients were significantly higher than those found in the dipyrone-treated patients [92 +/- 86 vs. 42 +/- 49 IU (p less than 0.02) for AST and 12 +/- 6.0 vs. 7.0 +/- 2.0 mumoles per liter (p less than 0.01) for bilirubin]. The cumulative dose of paracetamol in those who had impaired liver function was higher than that ingested by patients who did not develop liver damage, although still within the usual therapeutic range [11.6 +/- 5.8 vs. 7.6 +/- 4.2 gm (p = 0.02)]. The possible ways in which measles infection and paracetamol in combination can lead to hepatic damage are discussed.

[Percutaneous transluminal coronary angioplasty after coronary artery bypass]

Anginal syndrome may recur early of several years after coronary artery bypass surgery (CABS), and may be due to narrowing of a bypass graft, progression of pre-existing coronary artery lesions, or the appearance of new lesions. Repeat CABS is associated with considerable morbidity and mortality. We therefore performed percutaneous transluminal angioplasty (PTCA) in saphenous or internal mammary bypass grafts or native coronary arteries in 23 patients after CABS. We successfully dilated 35 of 37 lesions (95%) present in 33 of 35 vessels (94%) of 21 of 23 patients (91%). The mean vessel narrowing decreased from 86 +/- 22% to 13 +/- 19% (p less than 0.001) and in all 21 patients with angiographic evidence of success functional capacity improved. Single vein grafts were successfully dilated in 9 patients. None developed acute myocardial infarction or needed emergency surgery, but 1 had a cerebral embolism. PTCA is effective therapy for recurrent angina after CABS, and in many patients is preferable to another operation.

[Annulo-aortic ectasia]

Aortic regurgitation due to annular aortic ectasia was diagnosed in a 29-year-old woman with heart failure. The primary pathology of this disease is cystic medial necrosis of the ascending aorta with aneurysm formation and dilation of the aortic valve annulus. In successful surgical correction, the ascending aorta was replaced by a dacron prosthesis, the aortic valve by a prosthetic disc valve and the coronary arteries were reimplanted into the aortic graft.

Persistent painless ST-segment depression after exercise testing and the effect of age

The relation between the duration of ischemic ST-segment depression (1 mm or more 60 ms after the J point) and the clinical awareness of chest pain was studied in 31 patients (aged 39-73 years) undergoing symptom-limited, graded treadmill exercise testing. The response of these patients to nitrate therapy (spray or sublingual tablet) given immediately on cessation of exercise was also studied. During exercise, angina pectoris appeared at an estimated workload of 4.6 +/- 2.2 metabolic equivalents (METS) (mean +/- SD), and pathological ST-segment depression at 4.9 +/- 1.9 METS (p = NS.) On cessation of exercise, angina disappeared after 3.0 +/- 1.9 min, but ST-segment depression persisted for more than twice as long (6.6 +/- 4.1 min) (p less than 0.0001). The ratio of time to ST-segment recovery/time to relief of pain (a quantitative measure of silent ischemia during recovery) increased with age (r = 0.49, p = 0.002), and in 16 patients over 60 years of age was higher than in 15 younger patients (3.6 +/- 2.5 vs. 2.1 +/- 1.4) (p less than 0.04). The silent ischemia ratio after exercise tended to decrease, although not significantly so (p = 0.2), in patients who received oral nitrates; there was no difference in the response to spray or tablet in this regard. We conclude that ST-segment depression frequently persists after relief of exercise-induced angina pectoris and more so in elderly patients.

Effect of the second-generation calcium channel blocker nisoldipine on left ventricular contractility in cardiac failure

We studied the acute effects of nisoldipine, a new second-generation calcium channel-blocking drug, on cardiac hemodynamics and left ventricular (LV) contractility in 10 patients with grade 2 to 4 cardiac failure. Pressures were measured from an arterial line and a flow-guided catheter in the pulmonary artery, cardiac output by thermodilution, and LV ejection fraction simultaneously by radionuclide ventriculography. Ventricular loading conditions were altered by sublingual nitroglycerin to facilitate construction of LV end-systolic pressure (radial stress)-volume and stress-shortening curves. Nisoldipine, given by continuous intravenous infusion (0.12 micrograms/kg/min), reduced mean arterial pressure (p = 0.001), systemic vascular resistance (p less than 0.05), and the double product, a measurement of myocardial oxygen demand (p less than 0.01). Cardiac index, stroke index, and LV ejection fraction increased in 8 of the 10 patients. LV contractility was initially greatly reduced and was unchanged or slightly decreased during the administration of nisoldipine. Emax, the slope of the end-systolic pressure-volume curve, was unaltered in half of the patients and decreased in the others (NS), whereas the end-systolic stress-shortening curve did not change. In summary, nisoldipine has a potentially useful acute hemodynamic profile in patients with cardiac failure; it increases forward blood flow in most patients, decreases the determinants of myocardial oxygen demand, and produces little measurable changes in the inotropic state of the left ventricle.

Prediction of atrial and ventricular fibrillation complicating myocardial infarction from admission data: a prospective study

This study set out to examine prospectively two logistic formulae based on admission clinical data to predict ventricular or atrial fibrillation complicating acute myocardial infarction. A prospective study of 87 consecutive patients with acute transmural myocardial infarction was conducted. The formula for predicting ventricular fibrillation from the diastolic blood pressure, degree of ST-segment elevation, and QTc had a sensitivity of 93%, specificity of 83%, and a predictive value for an abnormal test of 62% (13 of 14 patients who developed ventricular fibrillation were identified). The formula for predicting atrial fibrillation from the age of the patient, a history of heart failure, systolic blood pressure, and four electrocardiographic parameters had a sensitivity of 78%, specificity of 85%, and a predictive value of 67% (14 of 18 patients identified). Our study shows that patients with myocardial infarction who are liable to develop ventricular or atrial fibrillation can be identified on admission from simple clinical data.

Left ventricular function during physiological cardiac pacing: relation to rate, pacing mode, and underlying myocardial disease

The hemodynamic effects of cardiac pacing at different rates and in different modes were studied in 21 patients who were candidates for permanent pacemaker implantation. Nine of these had primary conduction disturbances (PCD), ten had ischemic heart disease (IHD), seven with additional cardiac failure (CHF), and two had hypertrophic cardiomyopathy (HCM). In patients with PCD, atrial (AOO) and AV sequential (DVI) pacing did not change systolic blood pressure and pulse pressure but ventricular (VVI) pacing caused a progressive fall in these measurements, especially as heart rate increased. Ventricular volume and stroke volume (counts) derived from radionuclide ventriculography (RVG) decreased progressively with higher pacing rates, especially during VVI pacing. Cardiac output was maintained during VVI pacing by the increase in heart rate; during AOO and DVI pacing, cardiac output increased. Similar but more marked differences were observed in patients with IHD and CHF and the changes were even greater in the patients with HCM. Left ventricular (LV) ejection fraction changed little with increasing heart rate in PCD but decreased progressively with the onset of ischemia in IHD and CHF. There was no difference in ejection fraction in the different pacing modes. Graphs related to LV contractility (end-systolic pressure-volume relations) showed that AOO pacing produced the highest and VVI pacing produced the lowest curves of myocardial contractility in all patient groups, except that at higher rates the AOO curve shifted down again in patients with IHD and CHF, presumably with the onset of myocardial ischemia. This study showed that physiological pacing produced the best hemodynamic results in all patient groups. Higher pacing rates should be avoided in patients with ischemic heart disease while VVI pacing should not be used in patients with HCM. Blood pressure and RVG studies during temporary pacing are useful in selecting the optimal pacing system in an individual patient when the clinical choice is not clear.

Pyoderma gangrenosum complicating ulcerative colitis: successful treatment with methylprednisolone pulse therapy and dapsone

A 36-yr-old patient suffering from chronic ulcerative colitis complicated by severe pyoderma gangrenosum of the leg is presented. Pyoderma gangrenosum rapidly progressed and failed to respond to a combined treatment of bed rest, prednisone, sulfasalazine, povidone-iodine, compresses, and debridement. Pyoderma gangrenosum responded and disappeared with no recurrence during the following months after the combined treatment of methylprednisolone, dapsone, and zinc sulfate.

Atrial fibrillation in acute myocardial infarction

Atrial fibrillation (AF) complicating acute myocardial infarction (AMI) is associated with increased morbidity and mortality. Early intervention with antiarrhythmic treatment and hemodynamic support in patients prone to develop AF may modify their course. The purpose of this study was to characterize on admission the patients with AMI who are prone to develop AF. The admission data of 45 consecutive patients who developed AF during the course of AMI, and the data of a control group of 45 consecutive patients with AMI who did not develop AF, were analyzed using logistic regression. The following characteristics of patients who developed AF were identified: old age, history of heart failure prior to admission, low systolic blood pressure on admission, wide P waves, presence of left bundle branch block or left anterior hemiblock, marked ST segment elevation, and PQ segment depression (admission ECG). The logistic regression formula correctly classified 80 of the 90 patients (89%) to their actual group. The study showed that the relative risk of a patient with AMI to develop AF can be estimated on admission from simple, readily available, clinical data.

Short-term effect of nifedipine on effort tolerance in patients with angina pectoris

The short-term effect of oral nifedipine on effort tolerance was tested in 10 patients with effort angina pectoris and a positive effort test (GXT). The patients had four symptom-limited GXTs, using the Bruce protocol, on each day of the study at 0800, 1000, 1400, and 1800 hours. They received four doses of 10 mg oral nifedipine on one day and four doses of placebo on the other, each dose given half an hour prior to each GXT. Values with nifedipine were compared to values with placebo at the same time during each day. Nifedipine improved effort tolerance by 0.5 +/- 0.6 min (p = NS) on the first GXT (mean +/- SEM), by 1.2 +/- 0.6 min (p = NS) on the second GXT, by 1.0 +/- 0.3 min (p less than 0.01) on third GXT, and by 1.3 +/- 0.3 min (p less than 0.01) on the fourth GXT. Improvement of effort tolerance was associated with a fall in resting blood pressure and less ST depression; these changes were statistically significant only on the fourth GXT, which may indicate a cumulative effect of subsequent doses of nifedipine.

A simple prognostic index for hospitalized geriatric patients. A prospective study of 70 patients

A simple prognostic index for hospitalized geriatric patients is reported herein. Seven parameters including: mobility, sphincter control, mental competence, feeding ability, presence of pressure sores, medical condition and family state were recorded in 70 patients. The sum of the scores of all parameters constituted the prognostic index. At the end of 3 months the patients were divided into two groups: 18 patients who were discharged (group 1) and 52 patients who were still hospitalized (35 cases) or had died (17 cases) (group 2). The mean index for group 1 was 14.9 +/- 3.2 (mean +/- SD), while that for group 2 was 23.5 +/- 4.3 (p less than 0.00001). Eighty-three percent of the patients in group 1 and only 8% of those in group 2 had scored lower than 17. Thus, the score of 17 or more had a prognostic sensitivity of 92% and a specificity of 83%. The predictive value of indices of 17 or more was 94%. The index described offers therefore a simple and relatively accurate tool for the assessment of the prognosis of elderly patients.