Development of drug-risk assessment tool in the management of pulmonary hypertension with valvular heart disease

Abstract

The management of pulmonary hypertension (PH) with valvular heart disease (VHD) presents a few challenges, including delayed in definitive diagnosis, which results in delayed treatment intervention, unavailability and limited drug of choice, high cost of treatment and lack of expertise. Although cardiac surgery is the mainstay approach for PH with VHD, it carries a high risk of complications and is an expensive procedure. In treating underlying diseases and to avoid postoperative complications, pharmacotherapy management is the preferred option. The population of patients who receive pharmacotherapy has a high risk of developing drug-related problems, which demands immediate attention. This research aimed to develop the drug-risk assessment tool in managing patients PH with VHD. Overall, the research consisted of three main studies. The first study consisted of three projects. Project 1A, was to identify the specific types and patterns of drug prescribing pattern among PH with VHD. Project 1B was to evaluate on the effectiveness of sildenafil in PH with VHD through systematic review and meta-analysis, and Project 1C was to investigate on the effects of sildenafil in intraoperative parameters and patient survival rate within 5- years in PH with VHD. The second study was to determine the percentage of occurrence, types, and causes of DRPs among PH with VHD. The third study was to develop the drug-risk assessment tool (DRAT) and it's feasibility in real clinical practice. All studies were conducted at a single cardiology centre utilizing a retrospective study design, meanwhile the feasibility study was conducted prospectively. Sixty-one patients were included in this research. Patients were initiated and optimized with drugs before surgery for underlying diseases such as hypertension and atrial fibrillation, as recommended by recent international guidelines. Overall, the five most common used drugs were phosphodiesterase-5 inhibitors (100%), loop diuretics (95%), vitamin K antagonists (87%), beta-blocker (87%) and potassium chloride (79%). Patients were prescribed with phosphodiesterase-5 inhibitors (sildenafil) to reduce pulmonary artery pressure before and after surgery. A systematic review and meta-analysis of nine studies showed that sildenafil had little or no improvement in certain hemodynamic parameters. The role of sildenafil remains unclear and warrants further investigation. Second study demonstrated significant differences in median daily dose of sildenafil between groups (p < 0.001). Compared to pre- and post-induction during surgery, there was statistically significant improvement in cardiac index and systemic vascular resistance among patients (p<0.001). The timing of sildenafil initiation did not influence survival. The findings of third study showed sixty-one patients (100%) experienced at least one DRP. The total number of DRPs identified was 120 encounters associated with 503 causes. Finally, 14 causes were identified and included in the finalized DRAT form using the weighted scoring model method. In a feasibility study among seven clinical pharmacists and based on a system usability scale evaluation, the average score obtained was considered good according to the adjective rating scale at 70%. DRPs among PH with VHD were high and can be efficiently identify by using DRAT. DRAT is a promising approach and may be useful in various populations depends on data availability.