Israel Medical Association Journal

Background: Patients with mechanical prosthetic heart valves must be treated with vitamin K antagonists (VKA) due to an increased risk of valve thrombosis and systemic embolism.

Objectives: To assess the effects of the COVID-19 pandemic on VKA treatment control in patients with mechanical prosthetic heart valves.

Methods: We conducted a retrospective nationwide cohort study using the Clalit Health Services database. The cohort included patients who underwent either aortic or mitral valve replacement using a prosthetic mechanical valve. The primary outcomes included the overall time in therapeutic range (TTR) and the percent of patients with a TTR < 50% during the first year of the COVID-19 pandemic compared to preceding year.

Results: The cohort included 2381 patients. The percentage of patients who had at least two international normalized ratio (INR) tests during the first year of the COVID-19 pandemic was significantly lower compared to the year preceding the pandemic (81% and 87%, respectively, P < 0.001). In both years, the percentage of patients without any documented INR test was high (31.5% in the first COVID-19 pandemic year and 28.9% in the preceding year, P < 0.001). TTR was significantly lower during the 1st year of the COVID-19 pandemic compared to the preceding year (68.1% ± 26 and 69.4% ± 24, P = 0.03). A TTR > 50% was demonstrated in 78% and 81% during the pandemic and the preceding year, P = 0.009.

Conclusions: We noted overall poor VKA control in patients with mechanical heart valves. During the COVID-19 pandemic, VKA control became even worse as reflected by significantly lower TTR and INR tests rates.

Background: Factor VII (FVII) deficiency is characterized by normal activated partial thromboplastin time (aPTT) and prolonged prothrombin time (PT) values. It is diagnosed by determining protein level and coagulation activity (FVII:C). FVII:C measurements are expensive and time consuming.

Objectives: To analyze correlations between PT, international normalized ratio (INR), and FVII:C in pediatric patients before otolaryngology surgery and to establish alternative methods for identifying FVII deficiency.

Methods: FVII:C data were collected from 96 patients with normal aPTT and prolonged PT values during preoperative otolaryngology surgery coagulation workup between 2016 and 2020. We compared demographic and clinical parameters using Spearman correlation coefficient and receiver operating characteristic (ROC) curve analysis to determine the accuracy of PT and INR values to predict FVII deficiency.

Results: The median values of PT, INR and FVII:C were 13.5 seconds, 1.14, and 67.5%, respectively. In total, 65 participants (67.7%) displayed normal FVII:C compared to 31 (32.3%) with decreased FVII:C. A statistically significant negative correlation was observed between FVII:C and PT values and between FVII:C and INR. Despite statistically significant ROC of 0.653 for PT (P-value = 0.017, 95% confidence interval [95%CI] 0.529–0.776) and 0.669 for INR (P-value = 0.08, 95%CI 0.551–0.788), we were unable to determine an optimal cutoff point to predict FVII:C deficiency with high sensitivity and high specificity.

Conclusions: We could not identify a PT or INR threshold to best predict clinically relevant FVII:C levels. When PT is abnormal, determining FVII:C protein levels is needed for diagnosing FVII deficiency and considering surgical prophylactic treatment.