Coronary Artery Tortuosity and Spontaneous Coronary Artery Dissection: Association With Echocardiography and Global Longitudinal Strain, Fibromuscular Dysplasia, and Outcomes

BACKGROUND

The etiology and significance of coronary artery tortuosity (TCA) among patients with spontaneous coronary artery dissection (SCAD) are unknown. The aim of this prospective imaging cohort study was to report echocardiographic findings and evaluate whether TCA correlates with cardiac anatomy and function among patients with SCAD. Comorbidities including fibromuscular dysplasia (FMD) and outcomes were also assessed.

METHODS

TCA was determined on coronary angiography performed during the diagnosis of SCAD, and cardiac structure and function were evaluated using prospective comprehensive echocardiography.

RESULTS

Among 116 patients with SCAD, the mean age at echocardiography was 50.8 ± 8.8 years, a median of 10.9 months after SCAD. Sixty-two patients (53.4%) had FMD, 41 (35.3%) had histories of hypertension, and 17 (14.8%) were hypertensive during echocardiography. Most patients (n = 78 [69%]) had normal left ventricular geometry with normal median ejection fraction (61%; interquartile range, 56% to 64%) and normal global longitudinal strain (-22.2%; interquartile range, -24.0% to -19.9%). Fifteen patients (13.4%) had diastolic dysfunction that was associated with hypertension at the time of echocardiography. Patients with TCA (n = 96 [82.8%]) were older (mean age, 52.1 ± 8.0 vs 44.7 ± 9.9 years; P < .001) with a higher prevalence of FMD (59.4% vs 25%, P = .007) but a similar prevalence of hypertension (35% vs 35%, P > .99) compared with patients without TCA. Across the age range (31.5 to 66.9 years), each decade of age was associated with an approximately 0.89-unit increase in coronary tortuosity score (P < .0001). Echocardiographic parameters were not significantly different between the two groups. Median follow-up duration was 4.4 years (95% CI, 3.8 to 5.2 years). The Kaplan-Meier 3-year SCAD recurrence rate was 9.4% (95% CI, 3.7% to 14.8%). There were no deaths.

CONCLUSIONS

The majority of patients with SCAD had normal or near normal echocardiographic results, including global longitudinal strain, with no differences according to TCA. However, patients with SCAD with TCA were older, with a higher prevalence of FMD.

Retrograde Recanalization for Proximal Occlusion of the Right Renal Artery through a Compensated Collateral Artery in a 10-year-old Patient

BACKGROUND

To describe a retrograde recanalization for the proximal occluded lesion in right renal artery (RRA) in young patient with fibromuscular dysplasia (FMD).

METHODS

A 10-year-old girl presented to our hospital with proximal RRA occlusion and refractory hypertension though she took anti-hypertension medicines. Her renin and aldosterone were beyond the normal level in both base state and excited state. Her glomerular filtration rate at right kidney was only 18.4 ml/min. Angiography revealed proximal RRA occlusion and a compensated collateral artery (CCA) from the infrarenal aorta to the RRA. She was thus diagnosed with focal FMD. A retrograde recanalization was performed through this CCA.

RESULTS

Angioplasty and stenting were successfully performed to treat the proximal RRA occlusion. Postoperatively, the glomerular filtration rate in the right kidney improved. One-year follow-up revealed that, the blood pressure maintained at normal range without any antihypertensive agents. No other discomfort was complained.

CONCLUSIONS

It is feasible to establish a working pathway with patient's compensated collateral artery to treat the renal artery occlusion.

Renovascular Hypertension

Renovascular disease (RVD) is a major cause of secondary hypertension. Atherosclerotic renal artery stenosis is the most common type of RVD followed by fibromuscular dysplasia. It has long been recognized as the prototype of angiotensin-dependent hypertension. However, the mechanisms underlying the physiopathology of hypertensive occlusive vascular renal disease are complex and distinction between the different causes of RVD should be made. Recognition of these distinct types of RVD with different degrees of renal occlusive disease is important for management. The greatest challenge is to individualize and implement the best approach for each patient in the setting of widely different comorbidities.

Intraesophageal aortopulmonary collateral artery occlusion in an infant with Tetralogy of Fallot and flow-dependent major aortopulmonary collateral arteries

Patients with flow-dependent aortopulmonary collateral arteries often exhibit tenuous clinical statuses. Here we present an infant with Tetralogy of Fallot with pulmonary atresia (TOF-PA) and major aortopulmonary collateral arteries (MAPCAs) who experienced clinically significant oxygen desaturations during feedings. These frequent episodes were attributed to gastroesophageal reflux. In preparation for possible surgical correction of her complex congenital heart condition, she was intubated for a cardiac catheterization to better characterize her anatomy, but terminally decompensated shortly after extubation and restarting feeding. On autopsy, very mild evidence of esophageal reflux was present; instead, one of her four aortopulmonary collateral arteries was unexpectedly discovered traversing through the muscular layer of her esophageal wall. This finding was confirmed microscopically with significant intimal hyperplasia compared to uninvolved collateral arteries. The remainder of the autopsy findings, including her myocardium, lungs, and esophagus, were unremarkable. Given the feeding-associated oxygen desaturations present in life and the aberrant collateral artery's comparative stenosis at death, we speculate that the repetitive trauma of esophageal peristalsis was not only significant enough to temporarily impact oxygenation but, over time, led to near-occlusion of the intraesophageal collateral artery, which may have contributed to the terminal decompensation of this already tenuous patient.

An Unusual Case of Bilateral Upper Extremity Ischemia Caused by Forearm Vessel Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic disease that generally affects medium-sized arteries. The distribution typically involves the renal, extracranial carotid/vertebral, and iliac arteries. FMD in other vascular beds is rare. We herein present the case of a 47-year-old female with rapid-onset bilateral digital ischemia. Initial differential diagnosis included vasospastic disorders and vasculitis. An upper extremity arteriogram was suggestive of ulnar and radial FMD. Percutaneous intervention was not successful, and the patient was managed conservatively with symptomatic improvement. This case highlights the important diagnostic and therapeutic considerations in patients with less common etiologies of upper extremity ischemia.

Missense mutations in COL4A5 or COL4A6 genes may cause cerebrovascular fibromuscular dysplasia: Case report and literature review

INTRODUCTION

Fibromuscular dysplasia (FMD) is a rare and controversial disease that is seldom associated with genes. Here, we report the discovery of 2 missense mutations in COL4A5 and COL4A6 that may be risk factors for causing cerebrovascular FMD. We performed high-throughput sequencing on a patient with FMD and her probable healthy daughter, then annotated the frequency of a variant in a control or general population and assessed its deleterious effects according to published guidelines.

CONCLUSIONS

We identified missense mutations in COL4A5 (exon43:c.C3940 > T:p.P1314S) and COL4A6 (exon36:c.C3538 > T:p.P1180S) from the proband and her daughter. Sanger sequencing revealed that these probable causal variants were passed to her from her mother. The two missense mutations may have complex functional effects on the integrity of the cerebral vessel walls, including modulating collagens and promoting angiogenesis expression, may be responsible for cerebrovascular FMD.

[Renal artery stenosis]

Renal artery stenosis (RAS) is found in 1 to 2% of all hypertensive patients. Its diagnosis involves as a first step Doppler ultrasound and as a confirmatory test, CT scan or MRI. When the diagnosis isconfirmed, three questions should be addressed by the clinician: 1) the anatomical orm that is, fibromuscular dysplasia (FD) or atherosclerotic RAS (ARAS); 2) the potential relation between RAS and hypertension with major differences according to the two main etiologies; in the presence of FD hypertension is a priorir elated to the stenosis while it is not the case with ARAS; 3) is there an indication for revascularization with again two opposite situations. Renal angioplasty may cure up to one third of patients with FD and improve blood pressure control in some others and has thus to be discussed in this clinical context. On the contrary, several randomized trials have shown that the blood pressure benefit of renal revascularization is limited if any in ARAS and, above all, not associated with an improvement of cardiovascular and renal outcomes. Renal angioplasty should thus be restricted to highly selected patients while in all cases, cardiovascular prevention should be intensified, based on renin angiotensin system blockers, statins, and aspirin use. Whatever the management, these patients should be followed both on the renal side to detect restenosis or renal impairment, and on other cardiovascular complications particularly in the presence of ARAS.

The S curve: a novel morphological finding in the internal carotid artery in patients with fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease commonly affecting the renal and internal carotid arteries (ICAs). A previously unrecognized finding is a redundancy of the mid-distal ICA in FMD patients causing an 'S'-shaped curve. Carotid artery duplex ultrasounds were reviewed in 116 FMD patients to determine S-curve prevalence. FMD patients with an S curve were matched to four control patients divided equally into two groups: (1) age and sex-matched and (2) age ≥70 and sex-matched. S curves were present in 37 (32%) FMD patients. Of these, nine (24%) had angiographic evidence of FMD in their ICA only, 13 (35%) had renal artery FMD only, and 15 (41%) had both ICA and renal FMD. Two patients in the age and sex-matched group had S curves (odds ratio 16.86, 95% CI 3.92-72.48; p<0.0001) while 12 (16.2%) patients in the age ≥70 and sex-matched group had S curves (odds ratio 2.42, 95% CI 1.16-5.03; p=0.016). In conclusion, the S curve is a novel morphological pattern of the mid-distal ICA. While the S curve may not be specific, its presence in individuals <70 years old should alert the clinician to the possibility that FMD is present.

Heart rate variability and intima media thickness

Increased activity in the sympathetic nervous system is part of the physiological stress response and is expressed in the heart rate variability (HRV). The objective of this study was to examine associations of HRV and intima media thickness (IMT). In 2002, satisfactory measurements of HRV of 78 voluntary participants were made, both during a stress test and during sleep. IMT in 2002 and the progression in IMT from 1998 to 2002 were analyzed in relation to measures of HRV. HRV was negatively associated with IMT and IMT progression both during test and sleep. In men with higher IMT measures than mean the low frequency-high frequency ratio was higher during sleep than during test, perhaps mirroring a lack of ability to recovery. HRV was negatively associated with IMT and IMT progression. HRV may be part of the pathophysiological pathway between psychological strain and atherosclerosis.

Cardiac allograft vasculopathy: pathology, prevention and treatment

PURPOSE OF REVIEW

Cardiac transplantation is a recognized therapy for end-stage heart failure. Graft coronary artery disease is a chief determinant of long-term survival following cardiac transplantation. There are multiple purported etiologies for graft coronary artery disease including both immunologic and nonimmunologic factors. Immunologic factors include human leukocyte antigen mismatching, cytokine production, and activation of the cellular immune system. Nonimmunologic factors include diabetes, hypertension, hyperlipidemia, and cytomegalovirus infection, just to name a few. There are also donor and recipient factors including age, prior coronary artery disease in the donor heart, and mode of donor brain death.

RECENT FINDINGS

The diagnosis of graft coronary artery disease is especially difficult, partially due to the de-innervated allograft, as well as to its inherent predilection to affect the medium-sized and smaller arteries in a concentric and diffuse nature. Conventional angiography can overlook this condition because of the lack of eccentric plaques in larger epicardial arteries. Intravascular ultrasonography, by contrast, is more sensitive in detecting graft coronary artery disease but is unable to visualize the entire arterial system. Treatment is challenging and often unrewarding, leading to re-transplantation. Prevention is therefore ideal and involves protection against endothelial injury before and during transplantation as well as after transplantation, with decreased ischemic time, aggressive attention to early rejection, risk factor modification, and close follow-up.

SUMMARY

This review will look at the pathophysiology of graft coronary artery disease, current diagnostic and therapeutic choices, as well as existing and future directions.

Renal frame count: a quantitative angiographic assessment of renal perfusion

Renal perfusion may be measured by a variety of noninvasive methods; however, there is no objective angiographic method to assess renal perfusion. We measured the renal frame count (RFC) in 26 patients (50 kidneys) with normal renal function and normal renal angiograms and 9 patients (15 kidneys) with renal artery fibromuscular dysplasia (FMD) and normal renal function. The mean age of the patients with normal renal arteries was 61.5 +/- 9.5 (range, 47-82 years) and the mean age of patients with FMD was 72.5 +/- 9.2 (range, 54-86 years; P = 0.005). There was no correlation between the age and RFC in both the normal renal artery group and the FMD group. The mean RFC for the normal renal arteries was 20.4 +/- 3 (95% CI = 19.5-21.2), which was significantly lower than the FMD group's mean RFC of 26.9 +/- 9.9 (95% CI = 21.4-32.4; P = 0.0001). RFC is an objective angiographic measure to quantify renal perfusion. Compared to normal renal arteries, those with FMD had significantly increased RFC consistent with decreased perfusion.

Evidence for carotid and radial artery wall subclinical lesions in renal fibromuscular dysplasia

BACKGROUND

Fibromuscular dysplasia (FD) is a non-atherosclerotic, non-inflammatory arterial disease of unknown cause, and most frequently affects the renal and internal carotid arteries. Our objectives were to determine whether quantitative and qualitative lesions could be detected by high-resolution echotracking techniques at two arterial sites generally considered as free of echographic lesions: the common carotid and the radial arteries, and to compare their frequency with a control population.

METHODS AND RESULTS

We studied 70 patients with renal FD and 70 control subjects matched for age, sex and systolic blood pressure. Arterial parameters were determined using non-invasive high-resolution echotracking systems. Carotid B-mode scans and radiofrequency signals were analysed and quoted by three observers blinded to diagnosis. FD patients had thicker carotid (+12%, P < 0.001) and radial arteries (+10%, P < 0.05) than controls. Abnormal echographic patterns of the carotid artery, including supernumerary interfaces and/or interruption of the blood-intima acoustic interfaces, were frequently observed in FD patients and rarely in control subjects. These abnormalities were quantified with a phenotypic score ranging from 2 to 7, and their sensitivity and specificity were 73 and 81%, respectively, as markers of FD. Having a phenotypic score > 3 conferred an odds ratio of 12.9 (95% CI 5.7-29.3) of having renal FD.

CONCLUSION

We defined a new carotid phenotype in FD patients using a non-invasive echotracking system, and showed an increased wall thickness and distensibility of the radial artery. These data indicate the presence of subclinical lesions at arterial sites distant from the renal arteries, suggesting that renal FD is not a focal but a systemic arterial disease.

Spontaneous regression of two supraophthalmic internal cerebral artery aneurysms following flow pattern alteration

We report on a patient with fibromuscular dysplasia who presented with a right-sided giant calcified cavernous internal carotid artery (ICA) aneurysm and two additional supraophthalmic ICA aneurysms. Endovascular closure of the right ICA using detachable balloons was performed with collateralisation of the right hemisphere via the right-sided posterior communicating and the anterior communicating arteries. Repeat angiography after 6 months demonstrated spontaneous complete regression of the two supraophthalmic aneurysms, although the parent vessel was still perfused. In comparison to the former angiography, the flow within the parent vessel was reversed due to the proximal ICA balloon occlusion. MRI demonstrated that the aneurysms were not obliterated by thrombosis alone, but showed a real regression in size. This case report demonstrates that changes in cerebral hemodynamics potentially lead to plastic changes in the vessel architecture in adults and that aneurysms can be flow-related, even if not associated with high flow fistulas or arteriovenous malformations, especially in cases with an arterial wall disease.

Complementary roles of color-flow duplex imaging and intravascular ultrasound in the diagnosis of renal artery fibromuscular dysplasia: should renal arteriography serve as the "gold standard"?

OBJECTIVES

The purpose of this study was to compare color-flow duplex imaging (CFDI), intravascular ultrasound (IVUS), and renal arteriography in diagnosing renal artery (RA) fibromuscular dysplasia (FMD) and correlating with the hemodynamic response to balloon angioplasty (BA) in patients with drug-resistant hypertension.

BACKGROUND

Renal arteriography is generally regarded as the gold standard for diagnosing RA FMD. The observation that CFDI and IVUS depicted endoluminal abnormalities suggestive of RA FMD in some patients with normal renal arteriograms prompted comparison of these modalities in a consecutive series of patients.

METHODS

Twenty hypertensive patients with CFDI suggestive of RA FMD (mid-to-distal flow derangement and velocity augmentation) underwent renal arteriography, IVUS, and BA, with both immediate and long-term blood pressure (BP) response assessment.

RESULTS

All patients were women, aged 31 to 86 years (mean 62 years). On IVUS, various endoluminal defects (eccentric ridges; fluttering membranes; spiraling folds) were depicted at locations predicted by CFDI and were uniformly identified at sites where arteriography depicted classic evidence of FMD (8 patients). However, similar defects were detected by IVUS when angiography was borderline (7 patients) or normal (5 patients). Balloon angioplasty eliminated (16 patients) or reduced (4 patients) the IVUS findings and lowered systolic BP in all (mean reduction 53 mm Hg, p < 0.0001). This reduction was maintained during follow-up of 4 to 22 (mean 13) months (mean reduction 44 mm Hg, p < 0.0001), independent of baseline angiographic appearance.

CONCLUSIONS

Both CFDI and IVUS depict the blood flow and endoluminal abnormalities of RA FMD. Balloon angioplasty eliminates or improves IVUS findings and produces substantial, sustained BP reduction, an effect that is independent of baseline arteriographic appearance, calling into question the legitimacy of arteriography as the diagnostic gold standard.

Renal autotransplantation for vascular disease: late outcome according to etiology

PURPOSE

The purpose of this study was to evaluate the early and late outcomes of renal autotransplantation (RAT) according to the etiology of the underlying renal artery disease.

MATERIAL AND METHODS

Between January 1985 and April 2001, we performed 68 RAT procedures in 57 patients. The surgical indications were fibromuscular dysplasia (FMD) for 34 RAT procedures in 30 patients (11 men, 19 women; mean age, 41.3 +/- 14.6 years), Takayasu's disease (TD) for 26 RAT procedures in 19 patients (five men, 14 women; mean age, 33.0 +/- 12.3 years), and atherosclerosis for eight RAT procedures in eight patients (seven men, one woman; mean age, 66.5 +/- 7.9 years). The incidence rate of hypertension was 87% in patients with FMD and 100% in patients with TD and atherosclerosis. The incidence rate of renal dysfunction was 75% in patients with atherosclerosis, 27% in patients with FMD, and 16% in patients with TD. Autotransplantation was isolated in 31 cases and was associated with another vascular procedure in 37 cases, including 22 thoracoabdominal aorta repairs and 11 abdominal aorta or iliac artery repairs. The technique used to achieve renal revascularization was direct reimplantation in 17 cases and indirect reimplantation in 51 cases. The conduit used for indirect reimplantation was an arterial autograft in 42 cases, a vein autograft in seven cases, and a prosthetic graft in two cases. Simultaneous revascularization of the contralateral kidney was performed in 21 patients and included nine RAT procedures. Contralateral nephrectomy was performed in five patients.

RESULTS

In the FMD group, early segmental infarction was observed in four cases. Secondary nephrectomy was necessary in one case (at 88 months). Actuarial survival rates were 96.2% +/- 0.03% at 5 years and 84.1% +/- 0.11% at 10 years. Secondary patency rates were 100% at 5 years and 92% +/- 0.07% at 10 years. Hypertension normalized or improved in 96% of patients. Renal function improved in 50% of patients. In the TD group, one patient died of multiple organ failure 4 days after the procedure. Nephrectomy was necessary in one case. The actuarial survival rate was 94.7% +/- 0.05% and the secondary patency rate was 91.3% +/- 0.05% at both 5 and 10 years. Hypertension normalized or improved in 89% of the cases, and kidney function improved in all cases. In the atherosclerosis group, nephrectomy was necessary during the early postoperative period in three cases and during late follow-up in two cases (at 9 months and at 68 months, respectively). Actuarial survival rates were 54.7% +/- 0.2% at 5 years and 18.2% +/- 0.16% at 10 years. The secondary patency rates were 50.0% +/- 0.17% at 5 years and 33.3% +/- 0.18% at 10 years. Hypertension normalized or improved in 50% of cases, and kidney function improved in 33% of cases.

CONCLUSION

RAT is highly effective for treatment of complex renovascular lesions related to FMD and TD. Although RAT is less effective for atherosclerosis, it may be the only alternative in cases involving extensive renovascular disease.

Stroke in a young man with fibromuscular dysplasia of the cranial vessels with anticardiolipin antibodies: a case report

A case of fibromuscular dysplasia (FMD), presenting with a non-hemorrhagic infarct is reported. Positivity of anticardiolipin antibodies suggested an immune response. A 40-year-old man presented with sudden onset of stroke, preceded by similar ischemic attacks. Computed tomography (CT) of the brain showed a recent non-hemorrhagic infarct in the left middle cerebral artery (MCA) territory and an old right MCA territory infarct. Serum was positive for anticardiolipin antibodies. These above findings were confirmed at autopsy. A portion of the internal carotid artery and the middle cerebral arteries on both sides revealed features of FMD, with thrombosis. This case suggests an immune mechanism for FMD, hitherto unobserved in the cerebral circulation.

[Vascular biological aspects of thrombendarterectomy and alloplastic vascular replacement]

Irrespective of vascular approach and mode of repair any arterial reconstruction is charged by a procedural trauma and a desintegration of the vascular wall in its pathoanatomic structure. A number of specific repair mechanisms are set in motion by cellular and humoral mediators when non-endothelial layers get exposed to the lumen. Platelet deposition, local activation of hemostatic factors, intramural and wall-adjacent thrombus formation as well as subsequent proliferation of myofibroblasts are determinants of this process that may be characterized as a generalized wound healing response resulting in neointima formation. Exemplarily, the valency of endarterectomy and prosthetic grafting in the femoral axis is discussed on the background of recent experience in vascular biology.

Does prosthetic covering of nitinol stents alter healing characteristics or hemodynamics?

PURPOSE

To evaluate placement of polyester (Dacron) coverings on nitinol stents implanted in the canine aorta to determine the effect on cross-sectional lumen area, development of intimal hyperplasia, device endothelialization, and flow hemodynamics.

METHODS

Ten polyester-covered and 10 uncovered nitinol stents (60-mm length, 10- or 12-mm diameter) were deployed percutaneously in the normal infrarenal aorta of 20 adult mongrel dogs using random assignment. Angiography, intravascular ultrasound (IVUS), and duplex ultrasound performed at device deployment and before explantation at 6 weeks were used to measure aorta/device diameter and cross-sectional area. Pressure-perfusion-fixed aortic segments were compared for surface endothelialization (CD31 staining) and for thickness of neointimal formation.

RESULTS

All 20 endoluminal devices were accurately positioned in the infrarenal aorta without early or delayed evidence of device thrombosis, significant lumen narrowing, or device deformity. IVUS and duplex scanning identified no anatomical stenosis in either the covered or the bare devices by duplex ultrasound; peak systolic velocity measurements were similar (106+/-25 cm/s in the covered stent versus 96+/-25 cm/s for bare stents, p > 0.05). Mean neointimal thickness was significantly greater (p < 0.005) in the covered (326+/-145 microm) compared with the bare (219+/-62 microm) stents. Intima-to-media height ratios were greater in the covered stents (3.0+/-1.1 compared with 1.1+/-0.2, p < 0.003). Mean surface area endothelialization in the proximal, middle, and distal sections of each device was similar (p > 0.05) in covered (59%, 56%, and 69%) and bare (59%, 65%, and 53%) stents.

CONCLUSIONS

Deployment and balloon dilation of a covered nitinol stent in a nondiseased canine aorta increased neointimal development compared with an uncovered stent, but overall lumen cross-sectional area was preserved. No differences in device patency, intradevice thrombus formation, flow hemodynamics, or luminal endothelialization were demonstrated, despite a thicker intradevice neointima induced by the polyester covering.

Intracranial fibromuscular dysplasia in a six-year-old child: a rare cause of childhood stroke

Intracranial fibromuscular dysplasia is a nonatheromatous angiopathy that most commonly affects adult women and is rarely recognized in children. Symptoms include stroke and headache, although the vasculopathy may be asymptomatic. Diagnosis is based on angiographic appearance, commonly described as a "string of beads." The etiology of intracranial fibromuscular dysplasia is not known, although possible causes include genetic predisposition, trauma, and underlying connective tissue disease. Treatment of intracranial fibromuscular dysplasia is largely supportive once symptoms become manifest. We report a 6-year-old girl who presented to our center for further evaluation of a large left middle cerebral artery distribution infarction. The patient was previously healthy, without known risk factors for stroke. Initial symptoms consisted of a dense global aphasia and a right hemiparesis. On arrival, the patient's aphasia had improved but she continued to have significant deficits in both receptive and expressive language as well as residual right hemiparesis. Magnetic resonance imaging and conventional angiographic studies demonstrated characteristic beading of the distal portion of the left internal carotid artery, as well as the proximal middle cerebral artery. Laboratory evaluation, echocardiogram, and renal ultrasound were normal. The renal vasculature did not demonstrate evidence of intracranial fibromuscular dysplasia. In conclusion, intracranial fibromuscular dysplasia should be considered in the differential diagnosis of childhood stroke. When recognized, other sites of vascular involvement should be sought, and consideration of underlying disorders is important, as connective tissue disorders have been associated with a propensity to develop this vascular abnormality. Careful follow-up is warranted, due to possible progression of disease.

[Roles of arterial dysplasia, chronic ergotism and other factors in a case multiple spontaneous arterial dissections]

INTRODUCTION

Spontaneous dissection of cervical and visceral arteries are rare and usually associated with an underlying arterial disease.

EXEGESIS

The authors report the unusual case of a 50-year-old woman with high blood pressure who presented spontaneous dissection of cervico-cephalic, renal and hepatic arteries and of the descending aorta. She had been taking ergotamine tartrate for ten years for migraine. She also suffered from Raynaud's syndrome worsened by treatment.

CONCLUSION

The respective roles of arterial dysplasia, chronic ergotism, renovascular hypertension and migraine are discussed.

Hypothenar hammer syndrome: proposed etiology

PURPOSE

Finger ischemia caused by embolic occlusion of digital arteries originating from the palmar ulnar artery in a person repetitively striking objects with the heel of the hand has been termed hypothenar hammer syndrome (HHS). Previous reports have attributed the arterial pathology to traumatic injury to normal vessels. A large experience leads us to hypothesize that HHS results from trauma to intrinsically abnormal arteries.

METHODS

We reviewed the arteriography, histology, and clinical outcome of all patients treated for HHS in a university clinical research center study of hand ischemia, which prospectively enrolled more than 1300 subjects from 1971 to 1998.

RESULTS

Twenty-one men had HHS. All had occupational (mechanic, carpenter, etc) or avocational (woodworker) exposure to repetitive palmar trauma. All patients underwent upper-extremity and hand arteriography, unilateral in eight patients (38%) and bilateral in 13 patients (62%). By means of arteriogram, multiple digital artery occlusions were shown in the symptomatic hand, with either segmental ulnar artery occlusion in the palm or characteristic "corkscrew" elongation, with alternating stenoses and ectasia. Similar changes in the contralateral asymptomatic (and less traumatized) hand were shown by means of 12 of 13 bilateral arteriograms (92%). Twenty-one operations, consisting of segmental ulnar artery excision in the palm and vein grafting, were performed on 19 patients. Histology was compatible with fibromuscular dysplasia with superimposed trauma. Patency of arterial repairs at 2 years was 84%. One patient (5%) required amputative debridement of necrotic finger tips. No other tissue loss occurred. There have been no recurrences of ischemia in patients with patent bypass grafts.

CONCLUSION

To our knowledge, this is the largest reported group of HHS patients. The characteristic angiographic appearance, histologic findings, and striking incidence of bilateral abnormalities in patients with unilateral symptoms lead us to conclude that HHS occurs when persons with preexisting palmar ulnar artery fibrodysplasia experience repetitive palmar trauma. This revised theory for the etiology of HHS explains why HHS does not develop in most patients with repetitive palmar trauma.

Blood flow in distal end-to-side anastomoses with PTFE and a venous patch: results of an in vitro flow visualisation study

OBJECTIVES

non-physiological flow behaviour plays a significant role in the development of distal anastomotic intimal hyperplasia. To investigate flow patterns in four anastomotic types of femoral end-to-side distal bypass graft anastomoses, a flow visualisation study was performed.

METHODS

transparent 1:1 casted replicas of distal vascular graft anastomoses created by conventional technique, Miller-cuff, Taylor- and Linton-patch were fabricated. A pulsatile mock circulation with a high-speed video system was constructed. Flow pattern was determined at mean Reynolds numbers 100-500. Migrations of the stagnation points on the bottom of the anastomoses at mean Reynolds numbers 100, 230, and 350 were measured.

RESULTS

a vortex forms during early systole and increases to maximum systole in all anastomoses. During the diastolic phase the vortex moves in the Miller-cuff distally to the toe of the anastomosis and remains standing, while in the other anastomotic types the vortex moves proximally to the heal of the junction and breaks down. The shift of the stagnation point in the Miller-cuff was considerably smaller than in the other anastomoses.

CONCLUSION

conventional, Linton and Taylor anastomoses show similar flow patterns. The Miller-cuff with its wider cavity shows lower shift of the bottom stagnation point, but a persistent washout of the anastomotic cavity, which may contribute to its reported good clinical performance.

Elastase and the pathobiology of unexplained pulmonary hypertension

Our laboratory has focused on the increased activity of an endogenous vascular elastase in the pathobiology of pulmonary hypertension and on the mechanisms by which it is upregulated and by which it orchestrates abnormal remodeling of the vessel wall, specifically the induction of growth factors, the induction of the glycoprotein tenascin, which amplifies the proliferative response, and fibronectin, which is critical to the process of smooth muscle migration in the context of neointimal formation. We explore strategies by which targetting these processes might arrest progression or induce regression of pulmonary vascular disease associated with unexplained pulmonary hypertension.

The smooth muscle cell: sinner or saint in restenosis and the acute coronary syndromes?

Proliferation of arterial smooth muscle cells has held center stage as the culprit in restenosis for almost two decades. Many strategies for combating restenosis target smooth muscle replication. However, none have proven beneficial in clinical trials. Indeed, inhibition of smooth muscle proliferation in human patients might produce the undesired effect of destabilizing vulnerable atherosclerotic plaques because these cells furnish the collagen responsible for the biomechanical strength of the plaque. Actually, in some cases the benefit of angioplasty may depend on stimulating smooth muscle replication and collagen elaboration, converting an "unstable" to a more stable plaque. Moreover, recent clinical and experimental evidence suggests that restenosis depends less on neointimal hyperplasia than on constrictive remodeling (i.e., advential scarring, producing a smaller lumen), a process independent of smooth muscle replication. The recognition that plaques vulnerable to disruption often do not produce flow-limiting stenoses highlights a need for reassessment of the strategies to treat or prevent the acute coronary syndromes. We should strive to treat aggressively risk factors such as hyperlipidemia whose control appears to stabilize plaques. Trials are even underway comparing such risk factor management with coronary artery intervention. If we could identify potentially unstable atheroma before they are evident, clinically, we might even contemplate angioplasty of nonsignificant stenoses to induce smooth muscle cell proliferation and reinforce the plaque's fibrous cap. This proposal may seem preposterous, yet we perform "primary" angioplasty every day in patients with an acute myocardial infarction whose "culprit" lesions underlying the thrombus are often not critical. Our knowledge of the biology of restenosis has lagged behind our practice of coronary intervention. Advances in understanding the biology of the complications of interventional therapy, hand in hand with technical advances, should help us to devise more rational and enduring approaches to benefiting our patients.

Mediators of restenosis

The multitude of actions and interacting components involved in inciting and sustaining myointimal hyperplasia and restenosis effectively precludes the use of a single type of intervention. No pharmacologic approach has been conclusively shown to prevent coronary restenosis after balloon angioplasty or graft restenosis after peripheral arterial bypass. Although no human studies have been performed to prevent restenosis with gene therapy, the animal data are compelling, and the local delivery of various inhibitory agents may represent a novel way of preventing restenosis in vascular beds subjected to endovascular or traditional open procedures. Until these modalities are proved effective, the treatment of vascular stenosis due to internal hyperplasia remains within the domain of the surgeon.

Pathophysiology of restenosis: interaction of thrombosis, hyperplasia, and/or remodeling

In response to arterial injury, a series of intravascular changes take place that lead to restenosis: thrombosis, neointimal hyperplasia, and remodeling of the vessel. Neointima formation involves thrombosis, recruitment (migration), and recruitment/cell proliferation. To determine the source of neointimal cells that accumulate at the site of injury, pig models of stented and catheterized arteries were examined. The phases of neointima formation can each be seen in the pig in which neointimal cells come from nearby arterial tissue. The pig model was also employed to assess the effect of different degrees of force exerted by self-expanding stents on the arterial wall. In this model, the luminal area increased in response to chronic stent force. Slow expansion may help prevent neointimal hyperplasia and maintain luminal patency without causing damage to the artery.

Fibromuscular dysplasia of the internal carotid artery in a child with alpha-1-antitrypsin deficiency

Fibromuscular dysplasia (FMD) is a non-inflammatory segmental arteriopathy of unknown origin. Most often the renal arteries are affected, however, also mesenteric, lumbar, vertebral, or carotid arteries may be involved. FMD has frequently been reported as a cause of stroke in adults, but very rarely in children. We report the case of an 11-year-old boy who presented with an ischaemic infarction in the anterior part of the territory of the left middle cerebral artery. Angiography demonstrated a 'string of beads' lesion suggestive of FMD causing occlusion at the origin of the middle artery. Laboratory analyses revealed the protease inhibitor (Pi) phenotype SZ (PiSZ) of alpha-1-antitrypsin deficiency as well as decreased antioxidants and signs of enhanced lipid peroxidation. Such an imbalance may be associated with diminished resistance to oxidation, possibly causing direct cellular and tissue injury. Whether alpha-1-antitrypsin deficiency and an impaired status of antioxidants, as seen in our patient, might play a role in the pathogenesis of FMD is presently unclear.

Time course of coronary endothelial dysfunction in acute untreated rejection after heterotopic heart transplantation

BACKGROUND

Endothelial dysfunction is one of the early events leading to atherosclerosis. It occurs early after orthotopic heart transplantation and precedes the appearance of accelerated graft coronary artery disease believed to stem from chronic rejection of the endothelium. Acute rejection may contribute to the development of graft vasculopathy.

METHODS

To assess the time course and specific mechanisms of coronary endothelial dysfunction in acute untreated rejection, a swine model of retroperitoneal heterotopic heart transplantation was used. Large white swine (age 10 +/- 2 weeks, weight 25 +/- 5 kg) were serum-typed for class I antigen of the swine leukocyte antigen system and selected to ensure a similar degree of incompatibility. Donor hearts were preserved with normothermic blood cardioplegia and regional hypothermia; the mean ischemic time was 64 +/- 15 minutes. Myocardial contractility decreased from day 5 (normal) to day 14 (weak), but electrical activity was preserved. All coronary arteries were patent, and International Society for Heart and Lung Transplantation grade 4 rejection was present in all hearts beyond 5 days. The endothelial function of epicardial coronary arterial rings of native and transplanted hearts was studied in organ chambers filled with modified Krebs-Ringer bicarbonate solution and compared 1, 5, 9, and 14 days after transplantation.

RESULTS

Maximal endothelium-independent relaxations were unaffected at all stages. Endothelium-dependent relaxations to serotonin and alpha 2-adrenergic agonist UK 14304 (which activate receptors coupled to Gi-proteins) and to sodium fluoride (a direct G-protein activator) deteriorated progressively over time. At 14 days maximal relaxations to the calcium ionophore A23187, adenosine diphosphate, and bradykinin were also reduced, but to a lesser degree than those to serotonin and sodium fluoride. Histomorphometric studies of the allograft coronary artery rings showed progressive intimal hyperplasia from day 5 to day 14, with an increase in the incidence from 29% +/- 8.3% to 61.5% +/- 12%.

CONCLUSIONS

These studies show that endothelial dysfunction in untreated acute rejection after heart transplantation develops beyond 5 days and initially involves G-proteins; the dysfunction worsens over time to finally affect all endothelial mechanisms and vascular smooth muscle. The progression of the associated intimal hyperplasia parallels the alteration in endothelial function, suggesting a permissive role of the dysfunction in the development of this acute form of coronary graft vasculopathy.

[Natural history of renal artery stenosis]

The time delay necessary for the appearance of an atherosclerotic renal artery stenosis from the initial process of atherogenesis is not well known and is probably influenced by genetic factors and the classical risk factors (i.e. cholesterol, blood pressure levels...). The pathophysiology of fibromuscular dysplasic renal artery stenoses is even less known. Whatever the cause of a renal artery stenosis, blood pressure increases when the stenosis increases and becomes "significant" with a parallelism between the degree of the stenosis and the severity of hypertension. Renal artery stenoses can progress with time and lead to a complete occlusion of the involved renal artery. The progressive obstruction of the renal artery can lead to malignant hypertension and can also induce a gradual irreversible ischaemic renal damage leading to end-stage renal failure.

Fibromuscular dysplasia in intramuscular arteries of Japanese quail (Coturnix coturnix japonica)

Fibromuscular dysplasia (FMD) was found in the intramuscular arteries of both commercial (normal) and mutant (LWC) strains of Japanese quail. The mutant strain LWC is afflicted with an inherited muscular dystrophy exhibiting myotonia. The arterial lesions were classified as medial fibroplasia or medial hyperplasia, both being subtypes of medial FMD. Some lesions showed extensive proliferation of medial smooth muscle into the vascular lumen, resulting in partial occlusion of the affected blood vessel. FMD occurred more frequently in the mutant LWC quail than in the commercial strain. Ischaemic changes were absent in the associated muscle structures in both strains. The significance of FMD in relation to the skeletal muscle changes in the mutant LWC strain remains unclear.

Role of endothelium in thrombosis and hemostasis

Vascular endothelium is strategically located at the interface between tissue and blood. It is pivotal for protecting against vascular injury and maintaining blood fluidity. Normal endothelium releases prostacyclin and nitric oxide, potent inhibitors of platelet and monocyte activation and vasodilators. Their syntheses are governed by isoforms of enzymes. Normal endothelial surface expresses ecto-adenosine diphosphatase, which degrades adenosine diphosphate and inhibits platelet aggregation; thrombomodulin, which serves as a binding site for thrombin to activate protein C; and heparin-like molecules, which serve as a cofactor for antithrombin III. Normal endothelium secretes tissue plasminogen activator, which activates the fibrinolysis system. Endothelium produces and secretes von Willebrand factor, which mediates platelet adhesion and shear-stress-induced aggregation. Injury to endothelium is accompanied by loss of protective molecules and expression of adhesive molecules, procoagulant activities, and mitogenic factors, leading to development of thrombosis, smooth muscle cell migration, and proliferation and atherosclerosis.

The vascular biology of nitric oxide and its role in atherogenesis

Nitric oxide (NO), the biologically active component of endothelium-derived relaxing factor, has critical roles in the maintenance of vascular homeostasis. Decreased endothelial NO production, as a result of endothelial dysfunction, occurs in the early phases of atherosclerosis. NO appears to inhibit atherogenesis by inhibiting leukocyte and platelet activation and by inhibiting smooth muscle cell proliferation. Endothelial denudation is a prominent feature of vascular injury associated with percutaneous angioplasty, and decreased NO production appears to contribute to the restenosis process. Manipulation of the NO/cGMP signal transduction system may provide novel therapeutic approaches for limiting atherogenesis and neointimal proliferation in the future.

Renal artery velocity mapping with MR imaging

An MR phase imaging sequence with a very short echo time was used to assess blood velocity and flow at the renal artery bifurcation. Cardiac-gated MR imaging data were obtained in six healthy subjects in sagittal planes adjacent to the abdominal aorta and transverse planes above and below the renal artery bifurcation. Average renal artery flow rate was 23.8 +/- 9 mL/sec. A strong individual variability was found for the velocity profiles in the abdominal aorta during end-systolic regurgitation. Flow rate was also determined in three patients with reduced renal artery blood flow. Two patients received therapy with percutaneous transluminal angioplasty. The successful outcome was documented with MR imaging. A reliable assessment of renal artery flow with MR phase imaging is feasible. Measurement of the velocity profiles yields valuable insights in the complicated flow regime at the renal artery bifurcation.

Structural cardiovascular alterations and blood pressure variability in human hypertension

AIM

To evaluate the cardiovascular risk of hypertensive patients in relation to left ventricular hypertrophy, arteriolar hypertrophy and blood pressure variability, and the effects of antihypertensive treatment.

LEFT VENTRICULAR HYPERTROPHY

In hypertensive subjects with marked left ventricular hypertrophy, cardiovascular problems are about three times more frequent than in hypertensives who do not have left ventricular hypertrophy. The evidence suggests, however, that a moderate degree of left ventricular hypertrophy may be compensatory and that regression of mild hypertrophy should not necessarily be pursued.

ARTERIOLAR HYPERTROPHY

An increased wall to lumen ratio leads to an increase in vascular resistance and thus promotes hypertension. Regression of this alteration with antihypertensive treatment appears to be both beneficial and achievable, although it is not clear whether all antihypertensive agents have the same effect. Moreover, there are methodological problems in determining whether a regression has actually been achieved.

BLOOD PRESSURE VARIABILITY

There is evidence to suggest that end-organ damage is more frequent and more marked in hypertensives with greater 24 h blood pressure variability. It appears that antihypertensive treatment does not easily reduce this variability, although the intermittent measurements taken by automatic monitoring devices do not fully reflect patterns of blood pressure variation. It may be that hypertensives with a greater degree of blood pressure variability can obtain a reduction in the magnitude of this variability with antihypertensive treatment.

The heart and vascular changes in hypertension

AIM

To review present knowledge on the causes of cardiovascular changes in hypertension and on the effects of antihypertensive treatment.

BACKGROUND

The clinical manifestations of hypertensive heart disease have changed considerably in recent decades, from predominantly cardiac failure to predominantly left ventricular hypertrophy, which is an independent risk factor for all cardiovascular events. This change parallels the recent development of ultrasonic devices which make it possible to investigate the vessels as well as the heart. These devices have shown that there are different types of cardiac remodeling, which are associated with different hemodynamic profiles.

TREATMENT OF CARDIOVASCULAR REMODELING

Recent studies have shown that antihypertensive treatment, both pharmacological and non-pharmacological, can significantly reduce left ventricular hypertrophy in hypertensive patients without jeopardizing the hemodynamic balance. However, hypertensive vessel disease has been less extensively investigated, with many studies concentrating on the carotid arteries. There appears to be a correlation between cardiac and carotid artery changes but so far there is no information on the effects of the antihypertensive treatment on the carotid alterations.

Large artery function and alterations in hypertension

HYPERTENSION AND ARTERIAL HEMODYNAMICS: One of the characteristics of hypertension is an impairment in arterial hemodynamics. Any definition of hypertension has to take account of oscillatory fluctuations during the cardiac cycle, that is, fluctuations in systolic and diastolic blood pressure around mean arterial pressure. These fluctuations are determined by ventricular ejection, arterial distensibility and the timing of arterial wave reflections. EFFECTS OF AGING ON LARGE ARTERIES: Larger arteries stiffen progressively with age, due to medial and intimal thickening. This alteration can be described as a decrease in arterial distensibility (Di = delta D/delta P x D, where D is the diameter of the artery and P is the blood pressure). The most obvious consequence of arterial stiffening is an increase in the amplitude of pulse pressure, caused by an increase in systolic pressure and a decrease in diastolic pressure. Two mechanisms underlie this increase in pulse pressure: a higher incident pressure wave generated by the left ventricle into a stiffened aorta and an increase in the velocity of the pressure wave traveling forward and back in the arterial tree. In young subjects, the reflected wave causes an increase in the early diastolic wave, but in older people the reflected wave is summed with a late systolic wave, causing a dramatic increase in central systolic pressure. These phenomena affect left ventricular function adversely, increasing myocardial oxygen consumption and tending to decrease coronary blood flow. Furthermore, the increased systolic blood pressure induces left ventricular hypertrophy. EFFECTS OF ANTIHYPERTENSIVE DRUGS: Although all classes of antihypertensive drugs can reduce blood pressure, only some can decrease arterial distensibility. Angiotensin converting enzyme inhibitors and calcium antagonists have been shown to decrease the stiffness of conduit arteries and dilate peripheral arteries. This may account for the superiority of these drugs in regressing left ventricular hypertrophy.

Postoperative follow-up of fibromuscular subaortic stenosis

OBJECTIVES

This study attempted to determine whether early subaortic resection at lower levels of obstruction reduces the rate of recurrence of subaortic stenosis or reduces secondary damage to the aortic valve, or both.

BACKGROUND

Fibromuscular subaortic stenosis is a progressive condition, and at present it is unclear whether early operation reduces the recurrence rate along with decreasing the incidence of aortic insufficiency.

METHODS

Thirty-seven patients with fibromuscular subaortic stenosis and no other significant cardiac abnormality who underwent open subaortic resection were evaluated. The preoperative, early and late postoperative catheterization or echocardiographic findings as well as the operative reports were reviewed. The median age at operation was 6.4 years (range 1.1 to 17.3). The entire group has been followed up postoperatively for a median of 5.2 years (range 1.1 to 11). Mean systolic gradients across the left ventricular outflow tract were used for the purpose of this study.

RESULTS

There was a significant correlation between the preoperative mean systolic gradient and the incidence of preoperative aortic regurgitation and late postoperative aortic valve thickening as well as the incidence and degree of late postoperative aortic regurgitation. Late postoperative gradient and degree of aortic regurgitation correlated significantly with the follow-up interval. Aortic regurgitation was progressive in some patients despite subaortic resection. A preoperative mean gradient > 30 mm Hg provided a reasonable cutoff for the likelihood postoperatively of needing a reoperation, having a postoperative shelf, a thickened aortic valve, moderate aortic regurgitation or a gradient of > 10 mm Hg.

CONCLUSIONS

Our results suggest that although early subaortic resection may not reduce the rate of recurrence of fixed subaortic stenosis, it is likely to reduce acquired damage to the aortic valve.

Complex branch renovascular disease: management options and late results

PURPOSE

The purpose of this report is to review management options and late results of complex renovascular disease managed over the last 22 years.

METHODS

Complex branch renal artery disease in 84 kidneys was repaired during 75 operations performed in 68 consecutive patients. There were 61 females (90%) and 7 males (10%) whose predominant pathologic diagnosis was fibromuscular dysplasia manifesting as either renovascular hypertension or aneurysmal degeneration. These patients underwent 15 in situ, 52 ex vivo, and 8 combined reconstructions. In situ repair primarily with use of the bifurcated internal iliac artery autograft was used for primary lesions of the proximal renal artery bifurcation (two branches). Ex vivo repairs, primarily with use of the multibranch internal iliac autograft and hypothermic perfusion preservation, were used for all other patterns of distal renal artery branch disease and reoperative problems.

RESULTS

Renovascular reconstruction was successful in salvaging 83 of 84 kidneys (98.8%) in 67 of 68 patients. There were no operative deaths. Two reconstructions thrombosed in the early postoperative period. One was due to severe aortic disease, the other to branch artery dissection after a failed balloon angioplasty. Both patients continued to have hypertension. Before hospital discharge 65 patients had 81 renal revascularizations proven patent by arteriography. Their renal function was assessed and blood pressure was determined in a follow-up extending to 20 years (mean 7.5 years, median 7.9 years). Late arteriograms were obtained in 30 patients (46%) an average of 52 months after operation (range 6 months to 18 years). They demonstrate stable renal artery repair with no evidence of late graft failure in each. Hypertension was cured or improved in 51 of 53 patients (96%) with a proven patent reconstruction. Aneurysms were successfully repaired in 11 patients. Renal function was improved in four patients with ex vivo repairs, unchanged in 59 patients (15 in situ, 44 ex vivo), and persistently worse in only three patients, all of whom had in situ repairs.

CONCLUSION

The branched arterial autograft allows the restoration of normal renal arterial anatomy and function when inserted to replace complex distal renovascular disease. This provides a durable repair, essential for younger patients affected by this pattern of disease who anticipate a normal life span after renovascular repair. Successful long-term correction of diastolic hypertension and aneurysmal disease was accomplished without significant morbidity.

Pseudohypertension in a child with Williams syndrome

Pseudohypertension has often been reported in elderly subjects, but is an unusual phenomenon in children. We report the case of a 5-year-old child who presented with features of Williams syndrome (characterized by elfin facies, supravalvar aortic stenosis, and peripheral pulmonary artery stenosis). Repeated blood pressure recordings made with appropriately sized blood pressure cuffs were very high, while simultaneous intraarterial blood pressure was normal, confirming the presence of pseudohypertension. This was shown to be caused by excessively thickened arterial vessels.

Effects of a high-cholesterol diet on arterial wall thickness and vascular reactivity in young rabbits

Cholesterol enrichment of arteries may induce biochemical and structural abnormalities in vascular smooth muscle resulting in increased arterial contractile sensitivity. We studied the effects of a high-cholesterol diet on arterial structural properties and vascular reactivity in young rabbits. In vivo measurements of aortic intimal-plus-medial thickness using high resolution ultrasound imaging were obtained before and after 3 weeks of a high-cholesterol diet in 12 rabbits (group 2) and compared to data from 12 animals a cholesterol-free diet fed (group 1). Six rabbits (group 3) were studied before and after a 3-week, high-cholesterol diet and after a subsequent 13-week, cholesterol-free recovery diet. Blood pressure responsiveness to noradrenaline was evaluated before and at the end of each diet period. In groups 2 and 3, high dietary cholesterol caused an increase in intimal-plus-medial thickness from 0.31 mm and 0.33 mm to 0.88 mm and 0.89 mm, respectively (p less than 0.001). Plasma cholesterol concentration rose from 0.9 +/- 0.26 mmol/l to 36.7 +/- 8.56 mmol/l. There was no change in group 1. In group 3, intimal-plus-medial thickness remained increased (1.01 mm) following the cholesterol-free recovery diet despite normal plasma cholesterol. Blood pressure responsiveness to noradrenaline was markedly increased after the high-cholesterol diet (p less than 0.001) in groups 2 and 3 and after the cholesterol-free recovery diet in group 3 (p less than 0.001), and was directly related to intimal-plus-medial thickness (r = 0.84; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical spectrum of symptomatic external iliac fibromuscular dysplasia

External iliac fibromuscular dysplasia is a rare and usually asymptomatic disorder. We report eight symptomatic patients seen over a 15-year period and review pathophysiologic mechanisms accounting for the three following distinct lower extremity ischemic sequelae: (1) Emboli--episodic focal digital ischemia (blue toe) was seen in three patients. Resection and primary anastomosis of focal iliac ulcerative fibromuscular dysplasia (one patient) or resection and replacement (two patients) removed the embolic source and relieved the symptoms. (2) Chronic ischemia--gradual onset of full leg claudication in four patients was treated by operative graduated intraluminal dilation in three patients and prosthetic bypass in one. Arteriography subsequently showed a remodeled lumen in the three patients who underwent dilation. (3) Dissection--acute onset leg ischemia resulted from presumed dissection of the external iliac segment. After 4 months of conservative management of antiplatelet agents and exercise, symptoms resolved completely, and arteriogram showed spontaneous restoration of a normal lumen in the dissected segment. The clinical presentation of fibromuscular dysplasia may mimic other arterial processes such as atherosclerosis. Diagnosis is made only by arteriography with specific magnification views of the external iliac arteries and careful surveillance of the renal arteries. Appropriate treatment should be tailored to the clinical presenting symptom. For microembolic disease, resection and replacement are required. For chronic ischemia, intraluminal dilation is generally sufficient and durable and has proved to be a simpler and acceptable alternative to replacement or bypass. In acute dissection, surgical intervention may be deferred if the limb is viable to allow spontaneous healing and remodeling. Persistent symptoms may be the only indication for intervention in this ischemic manifestation of external iliac fibromuscular dysplasia.

Morphologic characteristics and functional significance of focal fibromuscular dysplasia of small coronary arteries

Focal fibromuscular dysplasia of small coronary arteries is not so rare as it is unrecognized. Although sometimes occurring as an isolated abnormality, it more often accompanies a variety of other lesions including inflammation or infiltration. In this review based on personal study of over 1,000 human hearts, the 3 topics include a description of the morphologic characteristics of the lesion, a discussion of its functional consequences affecting coronary flow, and an iteration of theoretical explanations for its development. The typical lesion is focal in distribution, is comprised of both fibrous and smooth muscle elements, and the histologic organization is one of dysplastic array. Included among the subjects discussed in functional consequences are coronary spasm, coronary reserve, chest pain, electrical instability of the heart, and comments on the role of focal fibromuscular dysplasia of small coronary arteries in hypertension, myocardial hypertrophy and heart failure. Theories as to its development include primary faults of smooth muscle or collagen, and focal abnormalities of clotting or neurovascular relation, but it is likely that the cause is multifactorial.