BALLOON ANGIOPLASTY OF CARDIAC VEIN IN CRT PATIENT BALON ANGIOPLASTIKA SRČANE VENE KOD CRT PACIJENTA

Introduction. Cardiac resynchronization therapy (CRT) reduces mortality and hospitalization in patients with symptomatic heart failure and left bundle branch block (LBBB) on optimal drug therapy. Among all, the reasons for “non-response” to CRT pacemaker could be the failure to achieve optimal left ventricular(LV) lead position, due to severe curve or stenosis/occlusion of target vein. Case report. We present a of male patient, age 79, NYHA class III, with atrial fibrillation, chronic coronary syndrome (CCS), prior myocardial infarction, who underwent coronary artery bypass surgery and mechanical prosthetic aortic valve implantation, indicated for CRT in whom venogram revealed ostial/proximal severe curve and stenosis of posterolateral vein, the only vein of coronary sinus leaded to anatomical optimal LV segment for stimulation. After the balloon angioplasty of curved and stenotic portion of target vein with compliant balloon 4.0 x 30 mm, satisfactory and stable position of quadripolar LV lead was achieved. Conclusion. Compliant balloon angioplasty could be safe and efficient way how to override severe coronary vein stenosis in some CRT cases.


Abstract
Introduction. Cardiac resynchronization therapy (CRT) reduces mortality and hospitalization in patients with symptomatic heart failure and left bundle branch block (LBBB) on optimal drug therapy. Among all, the reasons for "non-response" to CRT pacemaker could be the failure to achieve optimal left ventricular(LV) lead position, due to severe curve or stenosis/occlusion of target vein. Case report. We present a of male patient, age 79, NYHA class III, with atrial fibrillation, chronic coronary syndrome (CCS), prior myocardial infarction, who underwent coronary artery bypass surgery and mechanical prosthetic aortic valve implantation, indicated for CRT in whom venogram revealed ostial/proximal severe curve and stenosis of posterolateral vein, the only vein of coronary sinus leaded to anatomical optimal LV segment for stimulation. After the balloon angioplasty of curved and stenotic portion of target vein with compliant balloon 4.0 x 30 mm, satisfactory and stable position of quadripolar LV lead was achieved. Conclusion.
Compliant balloon angioplasty could be safe and efficient way how to override severe coronary vein stenosis in some CRT cases.

Introduction
Cardiac resynchronization therapy (CRT) is Class I indication for treatment symptomatic systolic heart failure (HFrEF), and QRS > 150 msec and left bundle branch block (LBBB) QRS morphology, on optimal drug therapy 1 .
One of the main reasons for "non-response" on CRT is suboptimal lead placement due to impassable target vein because of vein anatomy, i.e. severe curve or/and thrombosis/stenosis/ occlusion, which occurs in 1 -4 % of the cases 2 . One of the non routine option is to use PTCA (percutaneous transluminal coronary angioplasty) balloon.

Case report
We present a case of 79-year-old male patient, NYHA class III, with history of hypertension, chronic coronary syndrome (CCS), prior myocardial infarction, and who underwent coronary artery bypass surgery, together with implantation of mechanical prosthetic aortic valve six years ago. The patient was discharged from hospital next day without complication and with QRS narrowed for 40 ms, with normal biventricular capture (according to the lead V1/2). After four months of follow up the patient was referred as clinical "responder" (LVEF improved up to 45%), with evident signs of reverse remodeling, having one NYHA Class less and better tolerance of effort.

Although cardiac resynchronization therapy (CRT) is clearly indicated 3-5 in patients with
symptomatic HFrEF and optimal drug treatment, having complete left bundle branch block with a QRS duration > 150 ms, in sinus rhythm (Class IA) or atrial fibrillation (Class IIA), randomized controlled trials 6,7 reported 7.5% -10% of unsuccessful implantation due to failure of pacing the LV lead on optimal and stable position.
We presented a case of a 79-year old male patient with permanent atrial fibrillation, mechanical prosthetic aortic valve with indication for CRT pacemaker, with the proximal stenosis of posterolateral coronary vein, which aggravated optimal LV lead positioning.
After venous angioplasty with compliant PTCA balloon, optimal and stable position of quadripolar LV lead was achieved.
Multiple studies have reported the utility of applying interventional principles and equipment in coronary venosus circulation to accomplish optimal biventricular stimulation 8,9 . Luedorff et all 10 showed on retrospective analysis in single center with 705 CRT cases that in 3,5% of the cases venous angioplasty (balloon 3.0 mm in size usually) was needed and successfully performed. Moreover, the collateral veins also could be dilated in case of occlusion of big coronary vein branches, using small diameter guidewires and balloons 11 to retrogradely approach the target zone of latest activation of LV, but which is risky, delicate and prolonged procedure.
Some authors propose placing the stent on the stenotic portion of the vein (after the dilatation), but these could lead to post-procedural vein occlusion in short follow up period with further deterioration of LV ventricle function which would diminish the positive effect of CRT. Such a case was described in case report by Jachec´et all 12 , making these option obscure and potentially dangerous.
On the other hands, some implanters perform stent implantation in the veins in parallel to the LV lead, but for other reasons than because of stenosis 13 (to prevent lead dislodgement); in that case the potential huge technical and clinical problem would arise in case of need for extraction, therefore one should carefully analyze cost-benefit before the decision.
Finally, since the importance of reaching the optimal LV segment for LV stimulation was well established, and recently again emphasized (in 69% lateral or posterolateral segment 14 ), the present case report, which is the example of non routine approach and hasn´t been published up to now in domestic journals, showed the relatively easy and safe way to solve the problem of unpassable target vein by using only simple PTCA balloon. In our opinion the compliant balloon is better than non-compliant or semi-compliant balloon primarily because of safety issue with polyolefin copolymer material.

Conclusion
In case of vein stenosis which preclude placement of LV lead, balloon angioplasty is relatively easy and safe approach to facilitate the CRT procedure. Online First June, 2020.