Nonatherosclerotic Renovascular Hypertension

Renovascular hypertension (RVH) is a secondary form of high blood pressure resulting from impaired blood flow to the kidneys with subsequent activation of the renin-angiotensin-aldosterone system. Often, this occurs due to abnormally small, narrowed, or blocked blood vessels supplying one or both kidneys (ie: renal artery occlusive disease) and is correctable. Juxtaglomerular cells release renin in response to decreased pressure, which in turn catalyzes the cleavage of circulating angiotensinogen synthesized by the liver to the decapeptide angiotensin I. Angiotensin-converting enzyme then cleaves angiotensin I to form the octapeptide angiotensin II, a potent vasopressor and the primary effector of renin-induced hypertension. The effects of angiotensin II are mediated by signaling downstream of its receptors. Angiotensin receptor type 1 is a G-protein-coupled receptor that activates vasoconstrictor and mitogenic signaling pathways resulting in peripheral arteriolar vasoconstriction and increased renal tubular reabsorption of sodium and water which promotes intravascular volume expansion. Angiotensin II stimulates the adrenal cortical release of aldosterone, which promotes renal tubular sodium reabsorption, resulting in volume expansion. Angiotensin II acts on glial cells and regions of the brain responsible for blood pressure regulation increasing renal sympathetic activation. Angiotensin II simulates the release of vasopressin from the pituitary which stimulates thirst and water reabsorption from the kidney to expand the intravascular volume and cause peripheral vasoconstriction (increased sympathetic tone). All of these mechanisms coalesce to increase arterial pressure by way of arteriolar constriction, enhanced cardiac output, and the retention of sodium and water.

Spontaneous Coronary Artery Dissection: A Comprehensive Overview

Spontaneous coronary artery dissection is an underdiagnosed cause of acute coronary syndrome that primarily impacts young women. Spontaneous coronary artery dissection as a cause of acute coronary syndrome is not rare and should not be overlooked. Spontaneous coronary artery dissection should be considered on the list of differential diagnosis of any chest pain occurring in young women with few typical risk factors. The purposes of this article are to broaden the understanding and increase awareness of spontaneous coronary artery dissection, specifically its diagnosis and clinical outcomes.

High flow bypass for right giant cavernous internal carotid artery aneurysm with fibromuscular dysplasia of cervical internal carotid artery: microsurgical 2-D video

Background

It is well known that intracranial aneurysms can be associated to fibromuscular dysplasia (FMD). Nevertheless, it is not clear the best treatment strategy when there is an association of giant symptomatic cavernous carotid aneurysm with extensive cervical internal carotid artery (ICA) FMD.

Case Description

We present the case of 63 year-old right-handed female with hypothyroidism, 1 month history of right-sided pulsatile headache and visual disturbances with feeling of fullness sensation and blurry vision. Her neurological exam showed partial right oculomotor nerve palsy with mild ptosis, asymmetric pupils (right 5 mm and left 3mm, both reactive), and mild exotropia, normal visual acuity. Computed tomography angiogram and conventional angiogram showed 2.5 × 2.6 × 2.6 cm non-ruptured aneurysm arising from cavernous segment of the right ICA. She had right hypoplastic posterior communicant artery, and collateral flow through anterior communicant artery during balloon test occlusion and the presence of right cervical ICA FMD. The patient was started on aspirin. After lengthy discussion of treatment options in our neurovascular department, between observations, endovascular treatment with flow diverter device, or high flow bypass, recommendation was to perform high flow bypass and patient consented for the procedure. We performed right-sided pterional trans-sylvian microsurgical approach and right neck dissection at common carotid bifurcation under electrophysiology monitoring (somatosensory evoked potentials and electroencephalography); while vascular surgery department assisted with the radial artery graft harvesting. The radial artery graft was passed through preauricular tunnel, cranially was anastomosed at superior trunk of middle cerebral artery, and caudally at external carotid artery (Video). Intraoperative angiogram showed adequate bypass patency and lack of flow within aneurysm. The patient was extubated postoperatively and discharged home with aspirin in postoperative day 5. Improvement on oculomotor deficit was complete 3 weeks after surgery.

Conclusion

Nowadays, endovascular therapy can manage small to large cavernous ICA aneurysms even if associated to FMD, although giant symptomatic cavernous carotid aneurysms impose a different challenge. Here, we present the management for the association of symptomatic giant cavernous ICA aneurysm and cervical ICA FMD with high flow bypass. We consider important to keep the skills in the cerebrovascular neurosurgeon armamentarium for the safe management of these lesions.

Screening of extra-coronary arteriopathy with magnetic resonance angiography in patients with spontaneous coronary artery dissection: a single-centre experience

Background

Current consensus recommends extended vascular investigation in patients with spontaneous coronary artery dissection (SCAD). We here report our experience with the use of magnetic resonance angiography (MRA) for screening extra-coronary arteriopathy in patients presenting with SCAD.

Methods

Patients presenting with SCAD in a Spanish centre underwent prospective contrast-enhanced MRA to assess the cephalic and abdominopelvic arterial territories. Fibromuscular dysplasia (FMD) was diagnosed following European consensus criteria. Other vascular abnormalities were recorded separately. Two vascular radiologists supervised the acquisitions and independently analysed the results for all cases.

Results

Forty patients with SCAD [mean age 50.9±8.6 years, 90% (n=36) women] were included in the study, 12 patients declined to participate and 5 were excluded (metallic implanted devices). All enrolled patients underwent the screening protocol without complications. MRA demonstrated at least one extra-coronary vascular abnormality in 16 patients (40%): 5 (12.5%) were diagnosed with FMD, 6 (15%) showed arterial tortuosity, 3 (7.5%) had non-FMD focal stenoses, and 2 (5%) were found to have small aneurysms at the celiac trunk and splenic artery. No intracranial aneurysms were detected. At a mean follow-up of 4±3 years from the index episode, two cases experienced SCAD recurrences, one in a patient with FMD and the other one in a patient with arterial tortuosity. No deaths or strokes occurred.

Conclusions

Systematic extended vascular study with MRA was feasible and demonstrated associated extra-coronary arteriopathy in a substantial proportion of patients presenting with SCAD; however, none required additional intervention or led to vascular events. MRA, being a radiation-free modality, may be the preferred method for screening extracoronary arteriopathy in SCAD, a condition primarily affecting young and middle-age women sensitive to the risks of radiation.

Canadian spontaneous coronary artery dissection cohort study: in-hospital and 30-day outcomes

AIMS

Spontaneous coronary artery dissection (SCAD) was underdiagnosed and poorly understood for decades. It is increasingly recognized as an important cause of myocardial infarction (MI) in women. We aimed to assess the natural history of SCAD, which has not been adequately explored.

METHODS AND RESULTS

We performed a multicentre, prospective, observational study of patients with non-atherosclerotic SCAD presenting acutely from 22 centres in North America. Institutional ethics approval and patient consents were obtained. We recorded baseline demographics, in-hospital characteristics, precipitating/predisposing conditions, angiographic features (assessed by core laboratory), in-hospital major adverse events (MAE), and 30-day major adverse cardiovascular events (MACE). We prospectively enrolled 750 SCAD patients from June 2014 to June 2018. Mean age was 51.8 ± 10.2 years, 88.5% were women (55.0% postmenopausal), 87.7% were Caucasian, and 33.9% had no cardiac risk factors. Emotional stress was reported in 50.3%, and physical stress in 28.9% (9.8% lifting >50 pounds). Predisposing conditions included fibromuscular dysplasia 31.1% (45.2% had no/incomplete screening), systemic inflammatory diseases 4.7%, peripartum 4.5%, and connective tissue disorders 3.6%. Most were treated conservatively (84.3%), but 14.1% underwent percutaneous coronary intervention and 0.7% coronary artery bypass surgery. In-hospital composite MAE was 8.8%; peripartum SCAD patients had higher in-hospital MAE (20.6% vs. 8.2%, P = 0.023). Overall 30-day MACE was 8.8%. Peripartum SCAD and connective tissue disease were independent predictors of 30-day MACE.

CONCLUSION

Spontaneous coronary artery dissection predominantly affects women and presents with MI. Despite majority of patients being treated conservatively, survival was good. However, significant cardiovascular complications occurred within 30 days. Long-term follow-up and further investigations on management are warranted.

Accuracy of unenhanced magnetic resonance angiography for the assessment of renal artery stenosis

Purpose

To evaluate the accuracy of unenhanced magnetic resonance angiography (U-MRA) using balanced steady-state free precession (SSFP) sequences with inversion recovery (IR) pulses for the evaluation of renal artery stenosis.

Materials and methods

U-MRA was performed in 24 patients with suspected main renal artery stenosis. Two radiologists evaluated the quality of the imaging studies and the ability of U-MRA to identify hemodynamically significant main renal artery stenosis (RAS) defined as a stenosis ≥50% when compared to gold standard tests: contrast-enhanced magnetic resonance angiography (CE-MRA) (18 patients) or digital subtraction arteriography (DSA) (6 patients).

Results

A total of 44 main renal arteries were evaluated. Of them, 32 renal arteries could be assessed with U-MRA. When CE-MRA or DSA was used as the reference standard, nine renal arteries had hemodynamically significant RAS. U-MRA correctly identified eight out of nine arteries as having ≥50% RAS, and correctly identified 22 out of 23 arteries as not having significant RAS, with a sensitivity of 88.8%, a specificity of 95.65%, positive and negative predictive value of 88.8% and 95.65%, respectively, and an accuracy of 93.75%. Renal artery fibromuscular dysplasia (FMD) was observed in the two misclassified arteries.

Conclusion

U-MRA is a reliable diagnostic method to depict normal and stenotic main renal arteries. U-MRA can be used as an alternative to contrast-enhanced magnetic resonance angiography or computer tomography angiography in patients with renal insufficiency unless FMD is suspected.

Management of Renovascular Hypertension

Renal artery stenosis is a potentially reversible cause of hypertension, and transcatheter techniques are essential to its treatment. Angioplasty remains a first-line treatment for stenosis secondary to fibromuscular dysplasia. Renal artery stenting is commonly used in atherosclerotic renal artery stenosis, although recent trials have cast doubts upon its efficacy. Renal denervation is a promising procedure for the treatment of resistant hypertension, and in the future, its indications may expand.