[Safety and efficacy of percutaneous mechanical thrombectomy through ipsilateral calf venous access in the treatment of entire-limb acute deep venous thrombosis].

Objective: To evaluate the safety and clinical efficacy of percutaneous mechanical thrombectomy (PMT) through ipsilateral calf venous access in the treatment of entire-limb acute deep vein thrombosis (DVT). Methods: From July 2017 to August 2020, the clinical data of patients with entire-limb acute DVT at Renji Hospital, School of Medicine, Shanghai Jiaotong University treated by AngioJet through ipsilateral calf venous access were analyzed retrospectively. All patients received rivaroxaban or warfarin anticoagulant therapy for at least 6 months after operation. Pressure gradient socks were given routinely after operation. All patients were followed up at 3, 6, 12 months and every year after operation. The primary end points were the 12-month primary patency rate and the incidence of post thrombotic syndrome (PTS). The secondary end points included the thrombus clearance rate, total complication rate, bleeding complication rate and the 12-month incidence of moderate to severe PTS. Results: A total of 31 patients were included in the study. The age ranged from 31 to 80 (63±14) years, including 16 males and 15 females, 23 left lower limb DVT and 8 right lower limb DVT. There were 15 cases treated through peroneal venous access, 6 cases through anterior tibial venous access and 10 cases through posterior tibial venous access. Moreover, 9 cases underwent combined catheter-directed thrombolysis, 25 cases underwent iliac vein percutaneous transluminal angioplasty (PTA), and 10 cases underwent iliac vein stenting. The thrombus clearance rate was grade Ⅱ in 19 cases (61.3%) and grade Ⅲ in 12 cases (38.7%). One patient (3.2%) with anterior tibial venous access developed hematoma at the puncture site, which was improved after pressure bandage, and there were no other bleeding and serious complications. All the 31 patients were followed up for at least 12 months, with an average follow-up period of (22±9) months. The 12-month primary patency rate was 77.4% (24/31). The 12-month incidence of PTS was 16.1% (5/31) and the incidence of moderate to severe PTS was 3.2% (1/31). Conclusions: PMT through ipsilateral calf venous access is safe and effective in the treatment of entire-limb acute DVT. Thrombus in the distal popliteal vein can be one-stage removed and the incidence of PTS is low. It is considered as the first choice of access for the endovascular treatment of entire-limb acute DVT.

[Effects of morphine of different concentrations on myocardial action potential].

The effects of morphine at different concentrations on myocardial action potential were studied in isolated right ventricular papillary muscles of the guinea pig. It was observed that morphine at low concentrations (0.2-1.6 mumol/L) shortened the action potential duration (ADP) and effective refractory period (ERP) in a concentration dependent manner. These effects could be abolished by naloxone (1 mumol/L), phentolamine, tetraethylammonium (TEA) and cesium chloride (Cs+), but not by verapamil. On the other hand, morphine at high concentrations (15-120 mumol/L) prolonged ADP and ERP in a concentration dependent manner. The effects were unaffected by low dose of naloxone (1.2 mumol/L) but were abolished by high dose of naloxone (10 mumol/L), phentolamine, TEA, Cs+ and verapamil. These results suggest that morphine at low and high concentrations might stimulate different subtypes of opioid receptors. The effects of morphine in low concentrations are associated with the activation of potassium channel, whereas the effects of morphine at high concentrations are associated with the activation of potassium channel, calcium channel or calcium activated potassium channel. The action of opioid receptor was closely related to alpha adrenoreceptors.