Coronavirus disease-2019 (COVID-19) has surpassed 1.5 million confirmed cases in the United States with over 92,000 deaths. [1] COVID-19 has impacted healthcare systems worldwide affecting care and outcomes of non-COVID cardiovascular illnesses. [2, 3] However, impact on outcomes of patients with heart failure (HF) remains largely unexplored. Preliminary data suggest a decline in emergency department (ED) visits for HF during the pandemic, but with worse outcomes in hospitalized patients possibly due to patients' concern of COVID-19 exposure prompting late presentation. [4] [5] [6] We examined the impact of the COVID-19 pandemic on HF disease management through the lens of ambulatory hemodynamic monitoring of high risk patients.
We retrospectively reviewed all patients actively managed at our institution with pulmonary artery pressure (PAP) sensors 57 days before and after March 11, 2020 (declaration of state of emergency in Massachusetts). Patients with a left ventricular assist device or heart transplantation were excluded.
Patients recorded daily PAPs in the recumbent position using a wireless sensor. Routine review of PAP trends by clinicians was performed 1-6 times/month and concerning trends triggered clinician-patient contact. PAP volatility was defined as the difference between the measured PAP and a preset target PAP. Frequency of clinical activities, diuretic adjustments, follow-up visits, and worsening HF events (combining ED visits and HF hospitalizations (HFH)) were examined. Paired sample t-tests or Wilcoxon signed-rank tests were utilized for continuous variables depending on their distribution. Pearson Chi-square or Fisher's exact tests were used for categorical variables. This project was undertaken as a quality improvement initiative, and was exempt from ethics committee review per institutional policy.
Twenty-one patients met our inclusion criteria (mean age 60 ± 15 years, 14 (67%) women; 12 (57%) had preserved ejection fraction (LVEF≥50%) and 17 (81%) had hypertension). A total of 1162 hemodynamic transmissions were recorded, including 577 in the period prior to COVID-19 and 585 during the pandemic [median 49 (23-86) measurements per patient].
During the post-COVID period, PAP volatility increased with more frequent deviations above the preset PAP threshold (from a median of 4 per-patient (2-24) to 10 (4-26), p=0.170), but time-averaged PAP continuous measurements remained stable (35 ± 8 vs 37 ± 10, 18 ± 5 vs 18 ± 5, and 24 ± 6 vs 25 ± 7 for systolic, diastolic and mean PAPs before and after March 11 th , respectively, p>0.05 for all). (Figure 1 ) Clinician-initiated patient contacts increased during the pandemic (from a median of 3 per-patient (1-6) to 6 (3-9) p=0.003), with a total of 52 additional contacts for the aggregate cohort. The number of scheduled clinical visits (face-to-face or telemedicine) decreased in the post COVID period from 18 to 9 for the aggregate cohort, p=0.029. Finally, fewer worsening HF events were noted (1 vs 11, p=0.024) for the aggregate cohort in the post-COVID period. 
In this small cohort of high-risk patients managed with an implantable PAP monitor, PAP volatility increased during the COVID-19 pandemic, which may be due to reduced access to healthy food and exercise venues in the context of social distancing regulations. The increase in PAP volatility was effectively managed with a parallel increase in clinician-patient interactions. The result was that rather than an increase in hospital admissions, as might have been anticipated from the increase in PAP threshold crossings, fewer HFHs were observed during the pandemic. These data suggest that lower rates of HFH in our cohort are not entirely related to patients' reticence to seek medical care, but at least partly due to effective remote management.
The pandemic has strained healthcare systems worldwide, highlighting the need for effective strategies for remote management of patients with HF. A single-center Italian study reported 49% reduction in ED visits for HF in the post-COVID period but with nearly 3-fold increase in mortality in hospitalized patients, reflecting reluctance to seek 4 medical care. [6] In comparison, our study revealed stable clinical course and fewer HFHs, albeit in a small sample size, reflecting the potential role of PAP monitoring in managing patients particularly amidst a pandemic when they have limited access to direct medical care.
As we emerge from the pandemic, these lessons underscore the potential value of PAP monitoring and enhanced patient engagement in limiting the frequency of HF exacerbations. [7, 8] This analysis, however, should be viewed in the context of important limitations including small sample size, retrospective study design, highly selected patient cohort and short follow-up duration which cannot rule out the possibility of rebound increase in HFH as COVID-19 pandemic subsides. Larger studies are needed to validate the above findings. 