Data gathered from patients presenting with acute limb ischaemia (ALI) during the peak of the COVID-19 pandemic at the heart of New York City—a US epicentre—demonstrated a 50% rate of limb salvage as well as a 70% 30-day mortality rate, with 20% of that number among patients in whom revascularisation was attempted.
The research was conducted by investigators at New York-Presbyterian Queens hospital, and delivered by Vina Chhaya, a resident at the institution, during a recent session of the ongoing Eastern Vascular Society 2020 Virtual Meeting (7 October–18 November), a digital replacement for its annual gathering.
The research team was seeking to document its experience with revascularisation related to ALI among COVID-19-positive patients across a 10-week period spanning March–May, the height of New York City’s epidemic.
Chhaya explained: “The virus has systemic effects, including a disseminated intravascular coagulopathy associated with increased mortality risk. The exact pathology of this hypercoagulability is not completely elucidated, but proposed mechanisms include properties of the virus itself, a sepsis-mediated activation of the complement cascade, endothelial dysfunction, and antiphospholipid syndrome, as the virus induces the development of reactive antiphospholipid antibodies, predisposing patients to hypercoagulability.
“Data published to date focusing on hypercoagulability-induced acute limb ischemia from COVID-19 is primarily from Italy and consists of single-centre cohorts of around 20 patients,” she said. “Notably, the Italian experience highlights the significant increase of acute limb ischemia in COVID-19 patients but also demonstrates favourable revascularisation and survival-to-discharge outcomes. Given the associated dynamic coagulopathy, D-dimer has also emerged as a marker of thromboembolism that guides surveillance and timing of initiation of anti-coagulation.”
New York-Presbyterian Queens is an academic-community hybrid hospital located at the heart of where the city was fighting the coronavirus during the peak. Queens county itself recorded 71,000 cases and more than 6,000 deaths, Chhaya noted. Resources, she said, were limited and placed “tremendous strain” on the area’s healthcare system.
The study, based on a retrospective short review, scrutinised an institution with 535 beds, 2,232 COVID-19 patients, and 577 deaths. Some 14 cases of ALI were diagnosed, 10 of them among those with COVID-19—which, Chhaya speculates, was likely an underestimate given “the severe critical illness and deaths resulting from hypoxic respiratory failure as well as patients with chronic peripheral arterial disease avoiding the hospital at this time.”
Of the 10, 60% were Caucasian or Hispanic, seven were male, all were over the age of 50, and the main comorbidities recorded were hypertension and diabetes. The 10-patient cohort was further broken down into two subsets: interventions (n=5) and deaths (n=5).
“To understand how critically ill our 10 patients were, we examined vasopressor use, the maximal level of respiratory support utilised during hospitalisation, and functional status as documented in the patient chart,” explained Chhaya. “Surprisingly, the majority of our cohort did not require vasopressors, and 70% of patients used noninvasive positive pressure ventilation, with only two patients requiring intubation.”
Variables included body mass index (BMI), age and GOFAR score, a metric that predicts survival to discharge with good outcome following in-hospital cardiac arrest or attempted resuscitation.
“This score was used as a guide by our palliative care teams during the pandemic to have an objective measure for all critically-ill patients, and we included it in our dataset.”
Results showed that GOFAR scores appeared to be higher among the mortalities (mean: 27.6, 95% confidence interval [CI] 16.9–38.4) and lower for those who received interventions (mean: 14.8, 95% CI -1.52–31.2). D-dimer levels were noted to be elevated for the entire cohort (mean: 5,424ng/ml, 95% CI 1,199–9,648) and higher among the death subset (mean: 6,674, 95% CI -2,401–15,751). “Only three in our cohort had values less than 1,500ng/ml,” she said.
Among the intervention subset, the majority of the occlusion sites were in the lower extremity, with three in the infrapopliteal region. One patient received a bilateral below-the-knee amputation. Four of the five had Rutherford classification 2B or 3 ALI, two re-occluded and one patient died. Of those who re-occluded or died, all had Rutherford classification 2B or 3. Of the death subset, only one received a revascularization, with 80% of occlusions proximal, and all either Rutherford 2B or 3. Among this group, the survival-to-discharge probability as calculated by the GOFAR score was less than 3%.
Concluding, Chhaya said: “Overall, our data show a 50% limb salvage rate and a 70% 30-day mortality rate, with 20% among those patients receiving intervention. Despite our resource limitations during the peak of the pandemic, our team managed to perform a total of nine revascularization interventions, with four of those in COVID-positive patients initially presenting as Rutherford 2B or 3 ALI.”
She added: “Our data also support what has already been published, namely that D-dimer levels are higher in COVID-positive patients and especially so in those with acute limb ischemia as our cohort had a mean of over 5,000ng/ml. Finally, our high rates of morbidity and mortality are secondary to severe inflammatory response dates, leading to hypercoagulability as well as the critical illness seen in COVID-19 patients.”