Hyperphagia in male melanocortin 4 receptor deficient mice promotes growth independently of growth hormone

KEY POINTS

Loss of function of the melanocortin 4 receptor (MC4R) results in hyperphagia, obesity and increased growth. Despite knowing that MC4Rs control food intake, we are yet to understand why defects in the function of the MC4R receptor contribute to rapid linear growth. We show that hyperphagia following germline loss of MC4R in male mice promotes growth while suppressing the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. We propose that hyperinsulinaemia promotes growth while suppressing the GH-IGF-1 axis. It is argued that physiological responses essential to maintain energy flux override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth.

ABSTRACT

Defects in melanocortin-4-receptor (MC4R) signalling result in hyperphagia, obesity and increased growth. Clinical observations suggest that loss of MC4R function may enhance growth hormone (GH)-mediated growth, although this remains untested. Using male mice with germline loss of the MC4R, we assessed pulsatile GH release and insulin-like growth factor-1 (IGF-1) production and/or release relative to pubertal growth. We demonstrate early-onset suppression of GH release in rapidly growing MC4R deficient (MC4RKO) mice, confirming that increased linear growth in MC4RKO mice does not occur in response to enhanced activation of the GH-IGF-1 axis. The progressive suppression of GH release in MC4RKO mice occurred alongside increased adiposity and the progressive worsening of hyperphagia-associated hyperinsulinaemia. We next prevented hyperphagia in MC4RKO mice through restricting calorie intake in these mice to match that of wild-type (WT) littermates. Pair feeding of MC4RKO mice did not prevent increased adiposity, but attenuated hyperinsulinaemia, recovered GH release, and normalized linear growth rate to that seen in pair-fed WT littermate controls. We conclude that the suppression of GH release in MC4RKO mice occurs independently of increased adipose mass, and is a consequence of hyperphagia-associated hyperinsulinaemia. It is proposed that physiological responses essential to maintain energy flux (hyperinsulinaemia and the suppression of GH release) override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth. Implications of these findings are likely to extend beyond individuals with defects in MC4R signalling, encompassing physiological changes central to mechanisms of growth and energy homeostasis universal to hyperphagia-associated childhood-onset obesity.

Ghrelin

BACKGROUND

The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism.

SCOPE OF REVIEW

In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery.

MAJOR CONCLUSIONS

In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.

Percutaneous coronary intervention in the current era compared with 1985-1986: the National Heart, Lung, and Blood Institute Registries

BACKGROUND

Although refinements have occurred in coronary angioplasty over the past decade, little is known about whether these changes have affected outcomes.

METHODS AND RESULTS

Baseline features and in-hospital and 1-year outcomes of 1559 consecutive patients in the 1997-1998 Dynamic Registry who were having first coronary intervention were compared with 2431 patients in the 1985-1986 National Heart, Lung, and Blood Institute Registry. Compared with patients in the 1985-1986 Registry, Dynamic Registry patients were older (mean age, 62 versus 58 years; P:<0.001) and more often female (32.1% versus 25.5%; P:<0.001). In the Dynamic Registry, procedures were more often performed for acute myocardial infarction (22.9% versus 9.9%; P:<0.001) and treated lesions were more severe (84.5% versus 82.5% diameter reduction; P:<0.001), thrombotic (22.1% versus 11.3%; P:<0.001) or calcified (29.5% versus 10.8%; P:<0.001). Stents were used in 70.5% of Dynamic Registry patients, whereas 1985-1986 patients received balloon angioplasty alone. Procedural success was higher in the Dynamic Registry (92.0% versus 81.8%; P:<0.001) and the rate of in-hospital death, myocardial infarction, and emergency coronary bypass surgery combined was lower (4.9% versus 7.9%; P:=0.001) than in the 1985-1986 Registry. The 1-year rate for CABG was lower in the Dynamic Registry (6.9% versus 12.6%; P:<0.001).

CONCLUSIONS

Although Dynamic Registry patients had more unstable and complex coronary disease than those in the 1985-1986 Registry, their rate of procedural success was higher whereas rates of complications and subsequent CABG were lower. Results of percutaneous coronary intervention have improved substantially over the past decade.

The process of outcomes management in an acute care facility

Outcomes reports evaluate the care given to a patient population. The establishment of a system to collect, analyze, and report outcomes is essential because regulatory agencies require that comparisons of outcomes be made externally. The outcomes manager at Mission Hospital Regional Medical Center facilitated a team to evaluate the patient in active labor. The focus was to establish a process of care that would maintain quality of care and decrease the cesarean section rate. Cesarean section rate went from 22 percent to 16 percent. Customer satisfaction scores were elevated and financial outcomes or cost savings were $631,000 in 1998.

Psychosocial sequelae of visual loss in diabetes

This study evaluated whether degree of related visual impairment is associated with degree of psychological symptoms in general, and specifically more somatization, depression, anxiety, phobic anxiety, fear of hypoglycemia, and stress. A total of 49 volunteer subjects with diabetes-induced visual impairment were subdivided into totally blind and partially sighted groups, and were compared with 62 nonvisually impaired adults with diabetes. All were given the Brief Symptom Index, the Hypoglycemic Fear Survey, and the Perceived Stress Scale, along with a general questionnaire assessing demographic characteristics. Mean scores of the partially sighted group did not differ from the nonvisually impaired group, but the blind subjects reported more general psychological symptoms, somatization, anxiety, and phobic anxiety. Significantly more blind than sighted subjects exhibited clinical elevations on anxiety, phobic anxiety, and fear of hypoglycemia. Regression analysis confirmed the significant visual loss on psychological functioning and revealed large individual differences in how patients respond to visual loss. (ABSTRACT TRUNCATED)

Directional coronary atherectomy (DCA): a report from the New Approaches to Coronary Intervention (NACI) registry

Directional coronary atherectomy (DCA) with the Simpson coronary atherocath seeks to debulk rather than simply displace obstructive tissue and is a means of enlarging the stenotic coronary lumen. This report from the New Approaches to Coronary Intervention (NACI) registry describes the experience of 1,196 patients who underwent DCA as the sole treatment for either native vessel or vein graft lesions. Device success (post-DCA residual stenosis <50% and > or =20% improvement) was achieved in 87.8%, with a lesion success rate (postprocedural residual stenosis <50% and > or =20% improvement) of 94.0%. The mean resultant stenosis after all interventions (by core laboratory) was 19%. Significant in-hospital complications occurred in 2.8% of patients with DCA attempts, including death 0.6%, Q-wave myocardial infarction (MI) 1.5%, and emergent coronary artery bypass graft surgery (CABG) 2.8%. At 1-year follow-up, cumulative mortality was 3.6%, with repeat revascularization in 28% (repeat percutaneous transluminal coronary angioplasty, 20.1%; CABG, 10.6%). This reflected percutaneous or surgical revascularization of the original lesion (target lesion revascularization) in 22.6% of patients. Subgroup analysis showed a lower lesion success rate and an increased complication rate for unplanned use, vein graft treatment, and treatment of a de novo (vs a restenotic) lesion. Multivariate analysis shows that diabetes mellitus, unstable angina, treatment of a restenotic lesion, and greater residual stenosis after the initial procedure were independent predictors of the composite endpoint of death/Q-wave MI/target lesion revascularization by 1-year follow-up. Among these generally favorable acute and 1-year results, the NACI directional atherectomy data confirm the "bigger is better" hypothesis: that lesions with a lower residual stenosis after a successful procedure had significantly fewer target lesion revascularizations between 30 days and 1 year, with no increase in major adverse events.

Peptidases that degrade gonadotropin-releasing hormone: influence on LH secretion in the ewe

Several peptidases have been postulated to degrade the hypothalamic peptide gonadotropin-releasing hormone (GnRH), but it is not known if such enzymes contribute significantly to the delivery of GnRH to the pituitary in vivo. Furthermore, the activity of GnRH-inactivating peptidases may vary in different reproductive states, such as across the estrous cycle. In the present study, specific fluorescent substrates were used to measure the activity of the two major GnRH-degrading enzymes, prolyl endopeptidase (PEP) and endopeptidase 3.4.24.15 (EP 24.15), in soluble extracts of the median eminentes (ME) of ewes during different phases of the estrous cycle. Levels of EP 24.15 and PEP activity in the ME did not vary significantly across the cycle, although PEP activity was lowest at the time of the preovulatory luteinizing hormone (LH) surge. However, a statistically significant decline in PEP activity (18%, P = 0.02) was observed in the ME of OVX ewes in which a surge was induced by estrogen when compared to oil-treated OVX controls, suggesting a possible negative regulation of PEP activity by this steroid. The effect of intracerebroventricular (i.c.v.) infusion of several peptidase inhibitors on the pulsatile release of LH in the conscious OVX ewe was also examined. No consistent changes in the pattern of LH release were observed with i.c.v. infusion of the EP 24.15 inhibitor N-[1(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (cFP-AAY-pAB) or the angiotensin-converting enzyme (ACE) inhibitor captopril. Similarly, administration of the prolyl endopeptidase inhibitor bacitracin, or a more specific inhibitor of this enzyme, Z-Proprolinal (ZPP), did not alter LH release patterns. The results did not demonstrate a major role for changes in the activity of EP 24.15, PEP, or ACE in altering the pattern of GnRH secretion, but a minor reduction in PEP levels may occur at the time of the estrogen-induced LH surge.

Changes in the binding characteristics of the mu, delta and kappa subtypes of the opioid receptor in the hypothalamus of the normal cyclic ewe and in the ovariectomised ewe following treatment with ovarian steroids

The mu, delta and kappa opioid receptor subtypes were measured across the oestrous cycle of the ewe and in ovariectomised (OVX) ewes treated with oestrogen and/or progesterone. We have used a subtype-specific opioid receptor binding assay, in which [3H]diprenorphine non-preferentially labelled each receptor subtype in the presence of blocking concentrations of site-specific opioid analogues. The density and affinity of each receptor subtype was measured in the preoptic area (POA) of the hypothalamus and the mediobasal hypothalamus (MBH). Normally cycling ewes were killed during the luteal phase of the oestrous cycle and at various times after an injection of a synthetic prostaglandin (cloprostenol) to synchronise the onset of the follicular phase. OVX ewes were either untreated as controls (n = 4) or treated with oestrogen (n = 4), progesterone (n = 4) or oestrogen and progesterone combined (n = 4). The total number of opioid receptors did not alter across the oestrous cycle or with steroid hormone treatment. In the POA, the mean (+/- S.E.M.) number of delta receptors was significantly (P < 0.05) greater during the luteal phase than 24 h into the follicular phase (133 +/- 45 vs 35 +/- 8 fmol/mg protein). A significantly (P < 0.05) greater number of delta receptors was also found in the OVX progesterone-treated ewes compared with the control animals (172 +/- 9 vs 39 +/- 4 fmol/mg protein). In the MBH, the number of delta receptors was significantly (P < 0.01) greater in ewes killed 56 h after prostaglandin than luteal-phase ewes (184 +/- 40 vs 51 +/- 7 fmol/mg protein). The number of mu receptors in both the POA and the MBH was also significantly (P < 0.05) higher in the 56-h group than in the 12-h group. A similar trend was also observed in the steroid-treated animals, although differences did not reach statistical significance. The delta:mu ratio in the POA was significantly (P < 0.05) higher in the luteal-phase animals than any of the other groups killed after a cloprostenol injection that causes luteolysis. Similarly the ratio of delta receptor density to mu receptor density was greater (P < 0.05) in the OVX progesterone-treated ewes than in the OVX control ewes. No differences were found in the kappa receptor density across the cycle or with different steroid treatments. These data suggest that the relative proportions of the delta and mu subtypes of the opioid receptor in the hypothalamus change during the oestrous cycle. Regulation appears to be due to the feedback effects of ovarian steroids with progesterone altering the delta:mu ratio. In the MBH, there was a general increase in both delta and mu subtypes during the follicular phase of the oestrous cycle. This may explain, in part, how the responsiveness of the GnRH/LH axis to opioid peptides and antagonists changes across the cycle.

Coronary anatomic and procedural characteristics of patients randomized to coronary angioplasty in the Bypass Angioplasty Revascularization Investigation (BARI)

The Bypass Angioplasty Revascularization Investigation (BARI) is a randomized multicenter clinical trial that compares a strategy of initial coronary angioplasty to initial coronary bypass surgery for patients with multivessel coronary artery disease. The purpose of this report is to describe the coronary anatomic characteristics of the 915 patients assigned to the angioplasty arm of the trial and the manner in which angioplasty was performed. Patients were eligible for BARI if they demonstrated multivessel coronary artery disease, had a clinical indication for revascularization, and were suitable for both coronary angioplasty and bypass surgery. Clinical and technical features of angioplasty procedures were systemically recorded. Coronary cineangiograms obtained before and during the angioplasty were interpreted by a central radiographic laboratory. Angioplasty was performed in 904 (98.8%) of the 915 patients assigned to that initial strategy. Of 6,530 coronary arterial lesions identified, 3,427 (52.5%) were significant (> 50% diameter reduction). The majority of patients had 2-6 significant lesions, with 3 being most common. Angioplasty was attempted in 92.2% of the lesions for which it was intended. Lesions most frequently attempted ranged between 50% and 79% in severity. Multilesion angioplasty was performed in 77.5% of patients and 69.7% had multivessel angioplasty. Factors that influenced whether a lesion was attempted included lesion severity, clinical significance, and complexity. For lesions presenting as total occlusions, a history of recent infarction and postinfarction angina favored attempting angioplasty. Patients assigned to the angioplasty arm of BARI had evidence of extensive multilesion and multivessel coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous transluminal coronary angioplasty in African-American patients (the National Heart, Lung, and Blood Institute 1985-1986 Percutaneous Transluminal Coronary Angioplasty Registry)

Although black patients have a higher prevalence of risk factors for coronary artery disease, the outcome of coronary angioplasty in black patients is not known. The purpose of this study was to determine if any racial differences existed in the clinical characteristics and outcome of patients enrolled in the 1985-1986 National Heart, Lung, and Blood Institute (NHLBI) Percutaneous Transluminal Coronary Angioplasty (PTCA) Registry. The clinical characteristics, in-hospital event rates, and 5-year follow-up results of all patients enrolled in the 1985-1986 NHLBI PTCA Registry were examined with respect to race. Of the patients enrolled in the registry, 1,939 (90.8%) were white and 76 (3.6%) were black. Among black patients there were more women (50% vs 24%, p < 0.001), and more patients who had hypertension (73% vs 45%, p < 0.001) and diabetes (23% vs 13%, p < 0.05). Black patients were more likely to have multivessel disease (72% vs 48%, p < 0.001). Clinical success rates were similar (76.3% for blacks and 79.3% for whites), but because black patients had more vessels with significant disease, complete revascularization was achieved in 26% of black patients compared with 44% of white patients (p < 0.001). After the PTCA procedure there was no significant difference in major complications (death, myocardial infarction, or emergent coronary artery bypass grafting) between the 2 groups. Five-year follow-up data revealed that there was no significant difference in mortality, myocardial infarction, coronary artery bypass grafting, or repeat PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Multicenter clinical experience with rescue atherectomy for failed angioplasty

Directional coronary atherectomy (DCA) has been proposed as a "rescue" technique for failed or suboptimal percutaneous transluminal coronary angioplasty (PTCA) in an attempt to avoid myocardial infarction or emergency coronary artery bypass grafting. In this report we review the utilization and outcome of rescue atherectomy from the clinical experience of The Cleveland Clinic Foundation and Medical College of Virginia from November 1988 through January 1993, and from the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) database. This analysis includes 100 patients with 103 treated lesions from 44 patients at the Cleveland Clinic, 36 patients from the Medical College of Virginia, and 20 patients from the CAVEAT database. The etiology of failed PTCA was primarily from dissection in 52 lesions (50.5%), "recoil" in 43 lesions (41.8%), and recurrent thrombosis in 8 lesions (7.8%). Complete vessel closure was present in 23 lesions (22.3%). The vessels treated included 51.5% left anterior descending, 24.3% right coronary, and 16.5% circumflex coronary arteries. The average reference vessel diameter in the group was 3.10 +/- 0.06 mm (SEM), with an average stenosis of 78.9 +/- 1.2% before PTCA, 55.8 +/- 2.4% after PTCA, and 24.1 +/- 2.2% after rescue DCA. DCA was successful (Thrombosis in Myocardial Infarction [TIMI] grade 3 flow with > 20% stenosis reduction without death, Q-wave myocardial infarction, or coronary artery bypass grafting) in 94 of 103 lesions (91.3%). Complications included 1 patient with perforation (1%), 2 deaths within 24 hours (2.0%), and 6 patients requiring coronary artery bypass grafting (6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized trial of thrombolysis versus heparin in unstable angina

BACKGROUND

The clinical usefulness of intravenous thrombolytic therapy in unstable angina is currently unknown, despite the pathogenetic similarity of this entity to acute myocardial infarction, for which thrombolysis has enjoyed great success. To compare the clinical benefit of intravenous urokinase with that of conventional antithrombotic therapy in preventing the progression of unstable angina to new myocardial infarction, intractable angina, or death within the first 96 hours after hospitalization, 149 patients with unstable angina were randomized to one of two intravenous thrombolytic strategies.

METHODS AND RESULTS

Forty-nine patients received 3 million units urokinase i.v. over 90 minutes plus intravenous heparin (group A); 47 patients received unblinded 3 million units urokinase i.v. plus 325 mg aspirin p.o. daily (group B); and 53 patients received placebo thrombolytic infusion plus full-dose heparin (group C). The primary end point of this trial was 96-hour clinical status. There were no significant differences in the baseline characteristics (age, sex, previous myocardial infarction, hypertension prevalence, diabetes, tobacco use, or previous revascularization) among the three groups. Despite an excess of minor untoward reactions for the urokinase groups (chills, 26.5% and 23.4% for groups A and B versus 0% for group C; p < 0.01), there was no significant difference with respect to major bleeds (two, none, and two for groups A, B, and C, respectively; p = NS). At 96 hours after presentation, no significant difference emerged in the incidence of new cardiac events: new myocardial infarctions developed in 10.2% of group A, 6.4% of group B, and 3.8% of group C (p = NS); intractable angina occurred in 6.1% of group A, 10.6% of group B, and 9.4% of group C (p = NS). There were no deaths. All three groups encountered a similar incidence of overall cardiac events: 16.3%, 17.0%, and 13.2% for groups A, B, and C, respectively (p = NS). Although trial enrollment was to extend to 600 patients, interim analysis led to early cessation of enrollment due to a negative trend in respect to outcome after thrombolysis.

CONCLUSIONS

High-dose intravenous urokinase followed by either heparin or aspirin can be safely administered to a broad, unselected group of patients with unstable angina. However, this study suggests that no clinical advantage is conferred by urokinase, with either adjunctive antithrombotic therapy over standard heparin therapy alone, when given relatively late (mean, 8.7 hours) after admission for unstable angina. A possible detrimental effect cannot be excluded.

Multi-Hospital Eastern Atlantic Restenosis Trial. II: A placebo-controlled trial of thromboxane blockade in the prevention of restenosis following coronary angioplasty

Since platelet interactions appear to play an important role in the development of restenosis, attenuation of thromboxane-mediated reactions may improve the long-term outcome following coronary angioplasty. Phase II of the Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART) is a prospective, randomized, placebo-controlled study of thromboxane blockade in the prevention of restenosis following successful coronary angioplasty. Two forms of thromboxane blockade are evaluated: aspirin (a nonspecific inhibitor of thromboxane synthesis) and sulotroban (a specific thromboxane receptor antagonist). The design of this multicenter trial and the rationale for use of sulotroban in the prevention of restenosis are reviewed in this report.

Restenosis after coronary angioplasty: a multivariate statistical model to relate lesion and procedure variables to restenosis. The M-HEART Investigators

The Multi-Hospital Eastern Atlantic Restenosis Trial group obtained follow-up angiography in 510 patients with 598 successfully dilated coronary lesions who were enrolled in a controlled trial of the effects of a single dose of 1 g of methylprednisolone on restenosis after coronary angioplasty. The overall restenosis rate was 39.6%. The strongest univariate relations to the restenosis rate were found for lesion location (saphenous vein graft, 68%; left anterior descending artery, 45%; left circumflex artery and right coronary artery, 32%; p = 0.002); lesion length (less than or equal to 4.6 mm, 33%; greater than 4.6 mm, 45%; p = 0.001); percent stenosis before angioplasty (less than or equal to 73%, 25%; greater than 73%, 43%; p = 0.005), percent stenosis after angioplasty (less than or equal to 21%, 33%; greater than 21%, 46%; p = 0.017) and arterial diameter (less than 2.9 mm, 44%; greater than or equal to 2.9 mm, 34%; p = 0.036). Two multivariate models to predict restenosis probability were developed with use of stepwise logistic regression. The preprocedural model, which included only variables whose values were known before angioplasty, entered lesion length, vein graft location, left anterior descending artery location, percent stenosis before angioplasty, eccentric lesion and arterial diameter. The postprocedural model, which also included variables whose values were known after angioplasty was performed, was similar to the preangioplasty model except that it also entered postangioplasty percent stenosis and "optimal" balloon sizing but did not enter eccentric lesion. These data indicate that the probability of restenosis after angioplasty is determined predominantly by the characteristics of the lesion being dilated. They are consistent with the known intimal proliferative mechanism of restenosis, offer a means of identifying lesions at unusually high or low risk of restenosis, and of predicting the likelihood that a particular lesion will restenose after angioplasty and provide a rationale for stratification by restenosis probability in the design of future studies of restenosis.

Patient-related variables and restenosis after percutaneous transluminal coronary angioplasty--a report from the M-HEART Group

As part of a randomized prospective study designed to investigate the restenosis process after percutaneous transluminal coronary angioplasty (PTCA), the relation between patient-related variables and restenosis rate was examined. A total of 722 patients had successful PTCA. Angiographic follow-up was scheduled for 6 +/- 2 months after the procedure and achieved in 510 patients (71%), yielding 598 lesions for analysis. The overall restenosis rate was 40%. The rate was higher in patients undergoing early restudy for a clinical event than in those undergoing routinely scheduled follow-up restudy (71 vs 22%, p less than 0.0001). Age, sex, cigarette smoking history, diabetes mellitus and history of previous myocardial infarction were not associated with restenosis rate. Angina duration and severity before PTCA were also unrelated to restenosis rate. In summary, these variables, many of which have been previously implicated in restenosis, were not found to be predictors of restenosis. The decision to perform PTCA in individual patients should not be negatively influenced by the presence of these factors.

Multi-Hospital Eastern Atlantic Restenosis Trial: design, recruitment, and feasibility. M-HEART Investigators

A randomized control trial was set up to examine factors that influence restenosis and determine the effects of corticosteroids on restenosis following successful PTCA. The rationale for the study agent chosen, design, recruitment, and feasibility, as well as initial patient demographic data and initial results are presented.

A controlled trial of corticosteroids to prevent restenosis after coronary angioplasty. M-HEART Group

A multicenter, double-blind, placebo-controlled trial was conducted to determine if corticosteroids influence the development of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA). Either placebo or 1.0 g methylprednisolone (steroid) was infused intravenously 2-24 hours before planned PTCA in 915 patients. The PTCA patient success rate was 87% (mean) in the eight centers. There were no differences in clinical or angiographic baseline variables between the two groups. End-point analysis (angiographic restenosis, death, recurrent ischemia necessitating early restudy, and coronary artery bypass graft surgery) showed that there was no significant difference comparing placebo- with steroid-treated patients. Angiographic restudy showed the lesion restenosis rate to be 39% (120 of 307 lesions) after placebo and 40% (117 of 291) after steroid treatment (p = NS). We conclude that pulse steroid pretreatment does not influence the overall restenosis rate after successful PTCA.

Angiographic morphology of coronary artery stenoses in prolonged rest angina: evidence of intracoronary thrombosis

Previous clinical and angiographic/histopathologic correlative studies have demonstrated that angiographic findings of occlusive thrombus, intraluminal filling defects and complex lesion morphology indicate the presence of intracoronary thrombosis. The purpose of this study was to determine whether the presence of these descriptors of intracoronary thrombosis is associated with the syndrome of prolonged rest angina. The coronary angiograms of 50 patients with prolonged rest angina without myocardial infarction (group I) and 42 concurrent patients with stable angina (group II) were reviewed without knowledge of the clinical syndrome. Patients with prior myocardial infarction, coronary angioplasty or coronary artery bypass graft surgery were excluded, as were patients with important aortic stenosis. Each coronary artery stenosis in a major epicardial vessel was evaluated for the presence or absence of intracoronary thrombus (defined using standard criteria), complex lesion morphology (defined as the presence of haziness, a smudged appearance or irregular lesion margins) and eccentricity, and the frequency of each of these findings in groups I and II was compared. Intracoronary thrombus was present significantly more often in group I patients (42%) than in group II patients (17%) (chi 2 5.77; p less than 0.02). Complex lesion morphology was also present significantly more often in group I (44%) than in group II (14%) patients (chi 2 8.17; p less than 0.01). Either standard criterion for intracoronary thrombus or complex morphology was present in 70% of group I but only 21% of group II patients (chi 2 19.7; p less than 0.001). These results support a strong association of the angiographic descriptors of intraluminal thrombosis with the clinical syndrome of prolonged rest angina.(ABSTRACT TRUNCATED AT 250 WORDS)

Urokinase plus heparin versus aspirin in unstable angina and non-Q-wave myocardial infarction

The pivotal role of thrombosis in unstable angina and non-Q-wave myocardial infarction has been established recently. To assess the value and safety of thrombolytic therapy compared to conventional antithrombotic therapy (aspirin) in arresting progression in this setting to recurrent ischemic end-points, 25 patients presenting with unstable angina and an electrocardiogram showing subendocardial ischemia were randomized to receive either aspirin 325 mg daily, or urokinase 3 x 10(6) U intravenously, over 30 minutes followed by heparin. Incidence of endpoints (intractable ischemia requiring mechanical intervention, new myocardial infarction or death) was determined over 7 days. Coronary arteriography was performed at 24 to 72 hours to determine extent of coronary artery disease and morphologic severity of the culprit lesion, graded by a semiquantitative scoring system ranging from 4+ (definite thrombosis) to 0 (chronic lesion). In the first 24 hours, 7 of 13 aspirin versus 1 of 12 urokinase patients exhibited ischemia progression (p less than 0.05). By 7 days, progression to a primary ischemic endpoint occurred in 8 of 13 aspirin patients (3 myocardial infarctions and 5 intractable ischemias) versus 3 of 12 urokinase patients (2 intractable ischemias and 1 death) (p = 0.18). The apparent benefit of urokinase followed by heparin compared to conventional aspirin therapy in arresting early progression of unstable angina or non-Q-wave myocardial infarction was not associated with enhanced culprit lesion morphology (mean lesion severity score 2.7 +/- 1.5 vs 2.8 +/- 1.6 in aspirin-treated patients). Large scale, randomized trials to assess the clinical utility of urokinase for unstable angina are warranted.

Clinical risk factors for proliferative vitreoretinopathy

We reviewed the records of all patients with rhegmatogenous retinal detachments examined and treated by a single surgeon (B.P.C.) at the University of Virginia, Charlottesville, between 1978 and 1984. Of the 607 eyes that satisfied the selection criteria, a preliminary chart review of outcomes found that 65 (10.7%) had proliferative vitreoretinopathy and 34 had macular puckers. From the remaining 508 eyes, 325 controls were randomly selected to match each case from within a time window. Thirty-six (55.4%) of the 65 patients with proliferative vitreoretinopathy had had unequivocal reattachment after a single procedure before the onset of proliferative vitreoretinopathy, and the only clearly identified technical difficulty that was significantly more common in the patients with proliferative vitreoretinopathy was the inability to identify a retinal break. Several other features of the rhegmatogenous retinal detachments that correlated with the development of postoperative proliferative vitreoretinopathy were identified, and stepwise discriminant analysis was used to ascertain which of these were more important. The strongest predictor was use of vitrectomy in management of the detachment. Following this in order of importance were the presence of preoperative proliferative vitreoretinopathy, preoperative choroidal detachment, and the amount of cryopexy required. Vitrectomy remained a strong predictor even when considered after adjustment for all other characteristics. These data suggest that proliferative vitreoretinopathy is not simply an iatrogenic disease, but it is more likely to occur in association with certain detachment features that either by themselves or through their management require prolongation of the retinal wound healing process.

Retinal vascular occlusion without retrobulbar or optic nerve sheath hemorrhage after retrobulbar injection of lidocaine

We report a case of retinal vascular occlusion in a patient with severe diabetic retinopathy after retrobulbar injection of lidocaine. Several features of the occlusion are of interest: 1) rapid onset and relatively rapid reversal temporally associated with intervention; 2) numerous areas of focal vascular constriction; 3) absence of retrobulbar hemorrhage or dilated optic nerve sheath on CT scan; and 4) recurrence of nonperfusion after a second injection into the inferior peribulbar space. This suggests that patients with severe vascular disease may suffer retinal vascular occlusion after retrobulbar injections in the absence of identifiable retrobulbar or intraoptic nerve sheath hemorrhage. Though the mechanism is uncertain, this unusual complication deserves consideration, since its early recognition could possibly be of benefit in the management of some patients.

Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981. The National Heart, Lung, and Blood Institute Registry

In August 1985, the Percutaneous Transluminal Coronary Angioplasty Registry of the National Heart, Lung, and Blood Institute reopened at its previous sites to document changes in angioplasty strategy and outcome. The new registry entered 1802 consecutive patients who had not had a myocardial infarction in the 10 days before angioplasty. Patient selection, technical outcome, and short-term major complications were compared with those of the 1977 to 1981 registry cohort. The new-registry patients were older and had a significantly higher proportion of multivessel disease (53 vs. 25 percent, P less than 0.001), poor left ventricular function (19 vs. 8 percent, P less than 0.001), previous myocardial infarction (37 vs. 21 percent, P less than 0.001), and previous coronary bypass surgery (13 vs. 9 percent, P less than 0.01). The new-registry cohort also had more complex coronary lesions, and angioplasty attempts in these patients involved more multivessel procedures. Despite these differences, the in-hospital outcome in the new cohort was better. Angiographic success rates according to lesion increased from 67 to 88 percent (P less than 0.001), and overall success rates (measured as a reduction of at least 20 percent in all lesions attempted, without death, myocardial infarction, or coronary bypass surgery) increased from 61 to 78 percent (P less than 0.001). In-hospital mortality for the new cohort was 1 percent, and the nonfatal myocardial infarction rate was 4.3 percent. Both rates are similar to those for the old registry. The long-term efficacy of current angioplasty remains to be determined.

Intracoronary thrombolysis in acute myocardial infarction: clinical course following successful myocardial reperfusion

We reviewed the clinical course of 73 patients who had attempted intracoronary thrombolysis, with emphasis on follow-up. Fifty-nine patients (81%) had coronary reflow sufficient to control pain and injury current: 52 received thrombolysis alone and seven had thrombolysis combined with acute coronary angioplasty. Recurrent ischemic events in hospital were frequent and occurred in 17 patients (29%). These included silent reocclusion (four patients), recurrent angina (eight patients), and recurrent infarction in the same myocardial zone (five patients). Late ischemic events occurred in 11 patients (19%) and included silent reocclusion (two patients) and angina (nine patients). Although acute coronary angioplasty resulted in a high rate of successful myocardial reperfusion, long-term vessel patency was infrequent. The results of coronary bypass surgery, performed in hospital for severe residual coronary stenosis and angina and later for recurrent angina, were uniformly good. At follow-up of 6 to 36 months (mean 18.5 +/- 8.1), total mortality was five patients (8%). Only 16 reperfused patients (27%) were alive and well without recurrent ischemia or interventions. We conclude that reopening an acutely occluded coronary artery by thrombolysis and/or angioplasty can be performed in the majority of patients but must be regarded as initial therapy in view of the high incidence of recurrent ischemic events. Reperfused patients with stable myocardial blood supply post infarction have low long-term mortality.

Dysautonomia in mitral valve prolapse

Many of the clinical features of patients with mitral valve prolapse can logically be attributed to abnormal autonomic neural function. Accordingly, we have studied heart rate and blood pressure response to a standardized Valsalva maneuver and postural test in 44 untreated patients with demonstrated mitral valve prolapse. Fifteen healthy subjects of similar age served as controls. The directional changes of blood pressure and heart rate were similar in control subjects and patients in both tests, but patients differed from control subjects by their widely oscillating heart rate during the upright posture, and their exaggerated and prolonged bradycardia during the recovery phase of the Valsalva maneuver and following their return to recumbency in the postural test. This bradycardia persisted for 30 to 90 seconds after blood pressure returned to control values. Patients also showed a greater respiratory variation of R-R interval, which became especially marked during the adjustment to changes of posture. We postulate an abnormal central modulation of baroreflexes as the best explanation for the dysautonomic responses of symptomatic patients with prolapsed mitral valves.