Successful Secondary Endovascular Intervention in Pediatric Patients with Venous Thromboembolic Events

Background In the past, pediatric patients with venous thromboembolic events (VTE) were treated with low-molecular-weight heparin (LMWH) which was successful in around 70% of the cases. However, anticoagulation alone might not restore patency in all patients, and advanced therapeutic options to prevent postthrombotic syndrome are needed. During recent years, endovascular interventions have become a treatment option for pediatric patients with persistent thrombotic occlusion, not only in life- or limb-threatening VTE. Methods We evaluated 12 consecutive patients (11–17 years) with newly diagnosed VTE being treated at our department during the last 4 years (2017–2020). In case follow-up examination showed persistent venoocclusion under anticoagulation, patients received secondary interventional therapy like recanalization, percutaneous transluminal angioplasty with or without catheter-directed thrombolysis, and stenting. Patients with no clinical signs of venoocclusion or regredient thrombosis in imaging examination received anticoagulation alone. Results Six of 12 (50%) patients underwent catheter intervention. Median time from diagnosis to intervention was 4 months (0–12 months). Reintervention was necessary in one (8%) case and complete recanalization failed in one (8%) case. There were no major bleeding events or other major postinterventional complications, no acute or late local recurrence, and all patients reported clinical improvement after the procedure. Conclusion If endovascular intervention is used in teenage patients with persistent symptomatic VTE, reduction of postthrombotic symptoms is possible, even if intervention is performed secondary to failure of anticoagulation. Multidisciplinary treatment decisions can be based on the clinical course and follow-up imaging.

(More than) doubling down: Effective fibrinolysis at a reduced rt-PA dose for catheter-directed thrombolysis combined with histotripsy

Deep vein thrombosis is a major source of morbidity and mortality worldwide. For acute proximal deep vein thrombosis, catheter-directed thrombolytic therapy is an accepted method for vessel recanalization. Thrombolytic therapy is not without risk, including the potential for hemorrhagic bleeding that increases with lytic dose. Histotripsy is a focused ultrasound therapy that generates bubble clouds spontaneously in tissue at depth. The mechanical activity of histotripsy increases the efficacy of thrombolytic therapy at doses consistent with current pharmacomechanical treatments for venous thrombosis. The objective of this study was to determine the influence of lytic dose on histotripsy-enhanced fibrinolysis. Human whole blood clots formed in vitro were exposed to histotripsy and a thrombolytic agent (recombinant tissue plasminogen activator, rt-PA) in a venous flow model perfused with plasma. Lytic was administered into the clot via an infusion catheter at concentrations ranging from 0 (control) to 4.54 μg/mL (a common clinical dose for catheter-directed thrombolysis). Following treatment, perfusate samples were assayed for markers of fibrinolysis, hemolysis, and intact red blood cells and platelets. Fibrinolysis was equivalent between the common clinical dose of rt-PA (4.54 μg/mL) and rt-PA at a reduction to one-twentieth of the common clinical dose (0.23 μg/mL) when combined with histotripsy. Minimal changes were observed in hemolysis for treatment arms with or without histotripsy, potentially due to clot damage from insertion of the infusion catheter. Likewise, histotripsy did not increase the concentration of red blood cells or platelets in the perfusate following treatment compared to rt-PA alone. At the highest lytic dose, a refined histotripsy exposure scheme was implemented to cover larger areas of the clot. The updated exposure scheme improved clot mass loss and fibrinolysis relative to administration of lytic alone. Overall, the data collected in this study indicate the rt-PA dose can be reduced by more than a factor of ten and still promote fibrinolysis when combined with histotripsy.

Adjunctive Catheter-Directed Thrombolysis during Primary PCI for ST-Segment Elevation Myocardial Infarction with High Thrombus Burden

Background: High coronary thrombus burden has been associated with unfavorable outcomes in patients with ST-segment elevation myocardial infarction (STEMI), the optimal management of which has not yet been established. Methods: We assessed the adjunctive catheter-directed thrombolysis (CDT) during primary percutaneous coronary intervention (PCI) in patients with STEMI and high thrombus burden. CDT was defined as intracoronary infusion of tissue plasminogen activator (t-PA; monteplase). Results: Among the 1849 consecutive patients with STEMI, 263 had high thrombus burden. Moreover, 41 patients received t-PA (CDT group), whereas 222 did not receive it (non-CDT group). No significant differences in bleeding complications and in-hospital and long-term mortalities were observed (9.8% vs. 7.2%, p = 0.53; 7.3% vs. 2.3%, p = 0.11; and 12.6% vs. 17.5%, p = 0.84, CDT vs. non-CDT). In patients who underwent antecedent aspiration thrombectomy during PCI (75.6% CDT group and 87.4% non-CDT group), thrombolysis in myocardial infarction grade 2 or 3 flow rate after thrombectomy was significantly lower in the CDT group than in the non-CDT group (32.2% vs. 61.0%, p < 0.01). However, the final rates improved without significant difference (90.3% vs. 97.4%, p = 0.14). Conclusions: Adjunctive CDT appears to be tolerated and feasible for high thrombus burden. Particularly, it may be an option in cases with failed aspiration thrombectomy.

The Outcome of Catheter-Directed Thrombolysis in COVID-19-Associated Deep Vein Thrombosis

Introduction Published evidence of venous thrombotic complications of COVID-19 is lacking from India. This case series consists of twenty-nine adult patients who were COVID -19 positive and treated for Deep Vein Thrombosis (DVT) during the second wave of the COVID-19 pandemic, in India. The study was aimed at analyzing patient demographics of patients with DVT and the outcome of Catheter-Directed Thrombolysis (CDT) in COVID positive patients. Material and Methods: Patients who developed DVT while or after being COVID positive were managed between February and April 2021 at the institution of the first two authors and were included in this retrospective study. Demographic, clinical data, laboratory data, and treatment given were analyzed. All patients were followed up for 3 months with a Villalta score. Results: There were a total of 29 patients (12 male and 17 female) included in the study with a mean age of 47 ± 17 years. The average time of presentation from being COVID positive was 17.8 ± 3.6 days and one patient developed DVT after becoming Covid negative. All but one patient had lower limb involvement, with 42.8% having proximal and 57.2% distal DVT. All patients with Iliofemoral and two with Femoropopliteal DVT were treated with catheter-di thrombolysis and the other 15 patients were managed with anticoagulation alone. No re-thrombosis was observed in the thrombolysis group. Overall average Villalta score at 3 months was 10.7 ± 2.1 with a score of 10.58 ± 2.1 in the anticoagulation-only group and 10.85 ± 2.3 in the CDT group. Conclusion: COVID-19 seems to be an additional risk factor in the development of DVT. The outcome of such patients, treated by thrombolysis appears to be similar to non-COVID patients. In this, observational experience of the authors suggests that CDT could be offered to COVID positive patients with symptomatic Iliofemoral DVT with good outcomes and an acceptable post-intervention Villalta score.

COVID-19 Related Acute Lower Limb Ischemia Treated Via Percutaneous Thrombectomy and Catheter Direct Thrombolisis

Background: The aim of this report is to describe and discuss a unique case of acute lower limb ischemia presented in a recovered COVID-19 patient treated via percutaneous mechanical thrombectomy and catheter directed thrombolysis. Starting from this singular case a wide literature review regarding COVID-19-related thrombo-embolic complications has been accomplished. Methods: A 47-year-old male was admitted to the emergency unit with acute lower limb ischemia three weeks after testing positive for COVID-19. He had been isolated at home because of minor COVID-19-related symptoms. Angio-CT-imaging showed a segmental occlusion of the common iliac artery coupled with retro-articular popliteal artery and leg vessels thrombosis. The patient was first unsuccessfully submitted to trans-femoral iliac thrombo-embolectomy. Results: Instead of peripheral limb vessel re-thromboembolectomy, a percutaneous mechanical thrombectomy coupled with leg vessel catheter direct thrombolysis was performed. The completion angiography showed the recanalization of the popliteal artery and leg vessels as far as the ankle but with a reduced forefoot vascularization. The fibrinolytic treatment was continued for 8 hours post-operatively. A compartment syndrome complicated the early post-operative course. There was a progressive recovery of ischemic symptoms and at 6-month follow-up, peripheral pulses were palpable with an almost complete normalization of foot and toe perfusion and motility. Conclusion: Acute lower limb ischemia following COVID-19-related arterial thrombo-embolic events represents a severe complication of COVID-19 infection and may result in a high rate of revascularization failure. In these cases, Percutaneous Mechanical thrombectomy coupled with catheter directed thrombolysis might represent a less traumatic and more selective approach.

Efficacy of ultrasound assisted catheter-directed thrombolysis compared to catheter-directed thrombolysis in vitro

Background Catheter-directed thrombolysis (CDT) is an effective and safe endovascular method used in critical limb ischemia and many other thromboembolic events. Ultrasound-assisted catheter-directed thrombolysis (US-CDT) is an emerging technique considered to accelerate thrombolysis and therefore is supposed to improve outcome. Purpose To evaluate the efficacy of US-CDT in comparison to standard CDT in vitro. Material and Methods A total of 69 sets of human venous blood were evaluated, each comprising a tube just treated with CDT, a tube treated with US-CDT, and a control tube. All tubes were kept under physiological conditions. Except for the controls, in all tubes 5 mg of tissue-type plasminogen activator was administered over the predetermined treatment interval. Thrombus mass was weighted at the end of the lysis intervals at 6 h or 24 h, respectively. Results CDT led to a mean thrombus reduction of 32% and ultrasound-assisted lysis led to a mean thrombus reduction of 41% ( P < 0.001 for both). Thrombus reduction was significantly higher after US-CDT compared to CDT ( P = 0.001). The better efficacy of US-CDT was mostly already apparent at early phases during thrombolysis and did further mildly increase over time (r = 0.24; P = 0.047). Conclusion In vitro US-CDT is significantly superior to standard CDT; this effect is apparent at an early timepoint of lysis and slightly further increases over time.

Prevention of the post thrombotic syndrome with anticoagulation: a narrative review

The post thrombotic syndrome (PTS) is chronic venous insufficiency secondary to a prior deep vein thrombosis (DVT). It is the most common complication of VTE and, while not fatal, it can lead to chronic, unremitting symptoms as well as societal and economic consequences. The cornerstone of PTS treatment lies in its prevention after DVT. Specific PTS preventative measures include the use of elastic compression stockings (ECS) and pharmacomechanical catheter directed thrombolysis (PCDT). However, the efficacy of these treatments has been questioned by large RCTs. So far, anticoagulation, primarily prescribed to prevent DVT extension and recurrence, appears to be the only unquestionably effective treatment for the prevention of PTS. In this literature review we present pathophysiological, biological, radiological and clinical data supporting the efficacy of anticoagulants to prevent PTS and the possible differential efficacy among available classes of anticoagulants (vitamin K antagonists (VKA), low molecular weight heparins (LMWHs) and direct oral anticoagulants (DOACs)). Data suggest that LMWHs and DOACs are superior to VKAs, but no head-to-head comparison is available between DOACs and LMWHs. Owing to their potentially greater anti-inflammatory properties, LMWHs could be superior to DOACs. This finding may be of interest particularly in patients with extensive DVT at high risk of moderate to severe PTS, but needs to be confirmed by a dedicated RCT.

Endovascular revascularization strategies using catheter-based thrombectomy versus conventional catheter-directed thrombolysis for acute limb ischemia

Background Acute limb ischemia (ALI) is an important clinical event threatening both life and the affected limbs, but the optimal treatment for ALI remains undefined. The aim of this study was to compare the safety and effectiveness of thrombectomy approaches via either catheter-based thrombectomy (CBT) or catheter-directed thrombolysis (CDT). Methods A total of 98 patients (mean age 69.7 years, 60 male) who underwent endovascular intervention for ALI from January 2015 to July 2019 were included. Of these, 57 were treated with primary CBT via a large-bore catheter, an AngioJet catheter or Rotarex catheter, and/or underwent low-dose CDT, and 41 were treated with primary CDT. The safety and effectiveness of CBT compared to conventional CDT and other various endovascular techniques were evaluated. Results More Rutherford IIb patients were treated with primary CBT (68.4%) than CDT (26.8%; P < .001). Patients who underwent primary CDT achieved a higher technical success rate than those who underwent primary CBT in a shorter procedure time (P < .001), whereas 42.1% of patients who underwent CBT did not need adjunctive CDT. The duration and dosage of adjunctive CDT in the CBT group were significantly decreased compared with those in the primary CDT group (both P < .001), and the CBT group achieved a shorter in-hospital length of stay (P < .001). Subgroup analysis revealed that patients treated with AngioJet and Rotarex catheters achieved slightly lower dosages, shorter CDT durations and shorter in-hospital stay lengths than those treated with large-bore catheters (P > .05). Clinical success was estimated to be achieved in 98.2% of patients who underwent CBT, which is similar to the 97.6% estimated in those who underwent primary CDT (P = 1.000), and this finding was similar among the CBT subgroups. Patients who underwent CBT had a higher procedure-related distal embolization rate and economic cost than those who underwent primary CDT (P < .05), but it had slightly fewer complications than those who underwent primary CDT (P = .059), especially minor complications (P = .036). The freedom from amputation at 6 and 12 months for CBT and CDT was assessed (93.0% vs 90.2% respectively, P = .625; 89.5% vs 82.9%, respectively, P = .34,). Comparable limb salvage was found for different techniques of large bore catheters, AngioJet catheters and Rotarex catheters. The Kaplan-Meier table analysis also showed similar limb salvage rates between groups. Conclusions Endovascular treatment of ALI with the use of catheter-based therapies is an effective modality that can reduce the requirement for thrombolysis, with expected reductions in hemorrhagic complications, but at the risk of remediable distal emboli and increased economic cost. It has a similar clinical outcome to conventional CDT alone. Different CBT techniques have comparable efficacy but different adverse event profiles.