MP-2 - BALLOON PULMONARY ANGIOPLASTY VIA THE LEFT AXILLARY VEIN DUE TO A CONGENITAL DOUBLE INFERIOR VENA CAVA

Case background: A 74-year-old gentleman was referred to our pulmonary hypertension clinic with a 5-month history of worsening dyspnea on exertion. His past medical history was notable for unprovoked pulmonary embolism as well as obesity, obstructive sleep apnea, hypertension, type 2 diabetes mellitus and remote prostate cancer.
A transthoracic echocardiogram revealed an elevated estimated systolic pulmonary arterial pressure (PAP) of 56 mmHg. A ventilation perfusion study confirmed the diagnosis of Chronic Thromboembolic Pulmonary Disease (CTEPH). Right heart catheterization showed mean PAP of 33 mmHg, a pulmonary capillary wedge pressure (PCWP) of 17 mmHg and a pulmonary vascular resistance (PVR) of 2.2 Wood Units (WU).
Bilateral pulmonary angiography revealed chronic thromboembolic lesions that were deemed amenable to Balloon Pulmonary Angioplasty (BPA). Accessing the pulmonary vasculature via the femoral vein was technically challenging and suspected to be due to an interrupted inferior vena cava (IVC) draining into the superior vena cava (SVC) through an azygous vein. Subsequently, a computed tomography was performed to clarify vascular anatomy. A congenital double IVC was identified, accompanied by the absence of a suprarenal IVC with consequential renocaval venous drainage through the azygos vein into the SVC and drainage of the left IVC into the retroaortic left renal vein (Figure 1).
To avoid a two-operator technique usually necessary for internal jugular access, and to minimize radiation to the operator due to proximity to the image intensifier, left subclavian venous access was considered. Under ultrasound guidance, an 8 French Terumo sheath was inserted into the left axillary vein and sutured in place. Subsequently, a 6F Flexor® Shuttle® guiding introducer sheath was inserted in which a 100 cm multipurpose (MPA 1 Cordis Vista Brite Tip®) guiding catheter was advanced to access the pulmonary vasculature. An Asahi Sion® blue 0.014” wire was used to cross the lesions. Segments A1, A2, A3, A8, and A9 of the right lung were successfully dilated with 4-6 mm semi-compliant balloons without any complications. Mean PAP decreased to 27 mmHg post BPA with a PVR of 1.7 WU.

Management Challenges: BPA has become a class I indication for the management of patients with inoperable CTEPH or those with recurrent pulmonary hypertension after PEA. The technique is very well described in the literature. Vascular access via the femoral vein provides maximal support for catheter manipulation and exposes the operator to the least amount of radiation. Access through the internal jugular vein requires two operators (one to manipulate the guiding catheter and one to manipulate the guidewire) and results in higher radiation exposure.
In this particular case, femoral access would have precluded adequate catheter manipulation due to tortuosity and anatomic variability, and would have required the inevitable use of longer length of catheters. Internal jugular venous access was deferred due to the two-operator requirement and higher radiation exposure. Due to the absence of tortuosity and to facilitate catheter manipulation all the while limiting radiation exposure, we opted for access via the left axillary vein (Figure 2). Nonetheless, access through the right axillary vein could have been a viable alternative.

While technically more challenging, our case illustrates the feasibility, safety, and success of performing a BPA through the subclavian vein. Important teaching points include:
1. BPAs can be performed safely and successfully via the left subclavian vein in patients with anatomic vascular variants precluding use of conventional femoral access.
2. Adequate assessment of upper extremity venous anatomy is required prior to choosing an access site, to ensure no anatomic variability precluding this approach (ex: persistent left SVC).

To conclude, in symptomatic patients known for CTEPH for whom BPA is deemed to be the optimal therapy, BPA can safely be performed via the subclavian route when traditional femoral or internal jugular access are unavailable.