EVALUATION OF VASCULOGENIC ERECTILE DYSFUNCTION: AN ANGIOGRAPHIC ATLAS Herr, Allen1; Chen, Yibo1; McCullough, Andrew2; Mechlin, Clay2; Park, Susie1; Siskin, Gary1 1 Radiology, Albany Medical Center, Albany, NY, United States. 2 Urologic Institute, Albany Medical Center, Albany, NY, United States positive” angiogram. This is more likely to be an issue during ipsilateral selective INTRODUCTION angiography, since imaging within the 5-7 minute window after injection is eas- ily accomplished on the contralateral side when the injection is administered. In Erectile dysfunction (ED) is an important health issue that affects over 50% of this situation, evaluation of the cavernosal artery may be achieved by the intra- American men between the ages of 40-70 and as many as 150 million men world- cavernosal injection of Phenylephrine (500-100 ug), which reverses erection wide1. ED is defined as the recurrent inability to achieve and maintain an erect through local relative vasoconstriction. After 5-7 minutes detumescence occurs penis adequate for sexual function. It is now accepted that the cause of erectile and the cavernosal arteries can be visualized (Fig. 5). Cardiac monitoring during dysfunction is predominantly organic. Organic causes of ED can be further subdi- the Phenylephrine injection is important to assess for medication induced hyper- vided into vasculogenic, neurologic, hormonal, iatrogenic, traumatic, medication tension and bradycardia. If reversal of tumescence with Phenyleprine is required, induced, psychological or any combination of these causes. The penis is a hydrau- the best angiographic imaging of the cavernosal artery is accomplished during lic organ sensitive to inflow and outflow problems. It has been described as the the 5-7 minute window post injection and may require a series of angiograms. barometer of the health of the vascular system4. Vasculogenic ED can be due to impaired arterial inflow (Arterio-genic), inadequate cavernosal smooth muscle relaxation or inappropriate venous drainage (Veno-occlusive). Though in the early ROLE OF IR IN 1980’s the workup of erectile dysfunction frequently involved assessment of the vascular status of the penis with Doppler ultrasound and angiography2, the “goal MANAGEMENT OF ED oriented” approach promoted by Lue3 placed more emphasis on the treatment 1 2 and not the diagnosis of the underlying cause. The availability of PDE-5 inhibitors Percutaneous angiographic intervention for ED has been performed as early as all but eliminated the vascular workup. Though very effective in mild to moderate the 1980’s. During that time, the majority of interventions were performed on Fig. 1 (A) Pelvic arterial anatomy (B) Internal Iliac artery anatomy ED, the PDE-5 inhibitors are not as effective in more severe cases of ED. Patients Internal Pudendal Artery larger iliac arteries, and few interventions were performed on the smaller ves- failing treatment with PDE-5 inhibitors, constituting over 50%, are frequently Fig. 2 Cross-sectional anatomy of penile arterial supply. IPA-Internal pudendal sels13,14. With advancement of novel technology and materials, access to smaller- Artery, CPA- Common Penile Artery Common Penile Arteries asking why the medications are not working. Whereas in the vasculopath the caliber vessels has brought a resurgence of interest in angiographic intervention cause is obvious, many other men fail for undefined causes. With increased pub- Fig. 3 Schematic diagram of penile arterial supply. Adapted from Spiliopoulos, 2013. Internal Pudendal Artery for ED. Rogers et al. first described correlation between PDE-5i-resistant ED with lic awareness of the problem, men are seeking answers to the causality of their Fig. 4 IPA angiogram pre (A) and post (B) vasoactive intracavernosal injection. focal internal pudendal artery stenosis and proposed percutaneous revascular- ED. Men under 40 are presenting with devastating primary and secondary PDE-5 (A) High resistance in the CPA resulting in non-visualization of the CA and ization as a means of therapy15. The recent ZEN trial in 2009 was the first multi- inhibitor refractory erectile dysfunction. Whereas some may have rare congenital DPA. (B) Same patient after vasoactive intracavernosal injection now with center clinical trial to evaluate the use of a drug-eluting stent in treatment of IPA normal appearing CA and DPA. IPA- Internal pudendal Artery, CPA- Right Cavernosal penile arterial tree atresias, the erectile dysfunction in others may be a harbin- Artery stenosis in select patients with ED. Sixteen centers enrolled a total of 30 patients Common Penile Artery, DPA- Dorsal Penile Artery, CA- Cavernosal Artery. ger of serious systemic microvascular disease. The vascular workup of the penile Right Dorsal to evaluate response to endovascular intervention based on the International arterial tree is emerging as an important part of the diagnostic workup of PDE-5 Fig. 5 IPA angiogram (A) with pharmacological induced rigid erection resulting Artery Left Spongiosal Index of Erectile Function Questionnaire. The authors ensured that primary safety in compression of the cavernosal artery and (B) with detumescence after Artery inhibitor refractory erectile dysfunction. To this end, Doppler ultrasound offers a intracavernosal Phenylephrine administration showing a normal endpoints were met at 30 days: no deaths, perineal gangrene, or the need for re- non-invasive first line diagnostic modality for vasculogenic ED and is often com- Transverse Root intervention. At the end of 3 and 6 months, they report an increase of at least angiographic appearance of the same cavernosal artery. IPA- Internal Communication bined with pharmaco-stimulation using intra-cavernousal injection of vasoac- pudendal Artery, CPA- Common Penile Artery, DPA- Dorsal Penile Artery, Left Cavernosal Artery 4 points in the IIEF in more than half of their patients. The study demonstrates tive agents5. Intra-arterial digital subtraction angiography (DSA) can accurately CA- Cavernosal Artery Left Dorsal Artery that the use of Zotarolimus-eluting stents for percutaneous stent revasculariza- demonstrate pelvic and penile vascular anatomy to reliably detect steno-occlu- 3 tion of IPA stenosis is both feasible and is associated with clinically meaningful sive disease or anatomic variants that may explain suspected vasculogenic dis- improvement in symptoms of ED at six-month followup16. Gur et al. retrospectively ease.5,6,7,8,9,10 Cavernosal bypass surgery, popular in the 1980’s, fell into disfavor reviewed 36 patients who underwent endovascular intervention for ED based on because of its invasiveness and the disappointing short and long term results. two major criteria: non-responders to PDE-5i and suspected coronary artery dis- Penile vascular surgery is currently limited to men under 40 with discrete post- ease. Their findings were published in the 2013 PANPI trial (Pelvic Angiography traumatic arterial stenoses. Recently, endovascular treatment of aortoiliac dis- in Non-Responders to PDE-5i). The authors found atherosclerotic narrowing of the ease has been reported as safe and effective in improving sexual performance5,6. IPA similar to those in the coronary arteries with a slightly less average diameter. Data from the multicenter ZEN Trial (Zotarolimus-Eluting Peripheral Stent System The patients were asked to recall their sexual function before and 1 month after for the Treatment of ED in Males with Suboptimal Response to PDE5 Inhibitors) endovascular recanalization. More than half (61.5%) reported improvement from have reported encouraging results with placement of drug eluting stents in the impotence17. internal pudendal arteries7. Moving forward, endovascular therapies for ED are likely to be developed. It is essential that the interventional radiologist under- Treatment of veno-occlusive disease, including congenital causes such as arterio- stand penile arterial anatomy to maximize angiographic information in order to venous malformations, hemangiomas, or aberrant arterio-venous conduits, is to best treat the ED patient. occlude the venous outflow tract to allow maintenance of erection. Various tech- niques have been described and performed including percutaneous emboliza- tion which has shown various, non-definitive degrees of success18,19. ANATOMY & PHYSIOLOGY The role of endovascular therapy in the diagnosis and management of erectile 4 5 Penile erection is incited by various mechanisms. In brief, the neural stimulation dysfunction is evolving. Selected patients failing the PDE-5 inhibitors may bene- for erection originates from the S2-4 nerve roots. A complex reaction involving fit from endovascular reconstruction, including small drug eluding stents placed numerous hormonal signals such as nitrous oxide, dopamine, oxytocin, and sero- in the IPA, whereas others benefit from the potential angiographic identification tonin occur, which balance relaxation and contraction of cavernosal and arterial and clarification of the underlying etiology of their ED. The complexity of ED calls smooth muscle cells affecting erection. The achievement and maintenance of erection have an early branching pattern or a common trunk with the obturator artery. Brooks (DSA) allowing for definitive diagnosis and planning of treatment strategies, whether a upon a multi-disciplinary approach involving urology, cardiology, neurology, psychia- is the consequence of relaxation of the cavernosal smooth muscle allowing pooling of et al. describe three types of normal variant anatomy involving