At present, the technology of interventional treatment of patent ductus arteriosus (PDA) has been very mature, and in recent years, with the widespread use of domestic blockers, interventional treatment has become the preferred treatment method for PDA. From May 2007 to February 2010, we treated 382 patients with various types of PDA, including 25 patients with window-type PDA, accounting for 6.5%.
Materials and methods
All patients were diagnosed with PDA based on clinical symptoms, electrocardiogram, X-ray and echocardiogram. 22 patients had a continuous murmur and palpable tremor between 2 and 3 ribs at the left edge of the sternum, and 3 patients had only a systolic murmur. All patients had P2 hyperactivity.
Echocardiographic examination suggested left-to-right shunts at the level of the great vessels in 20 cases and bidirectional shunts (left-to-right shunts were predominant) in 5 cases; combined mitral regurgitation was mild to moderate in 3 cases, tricuspid regurgitation was mild to moderate in 5 cases, and aortic regurgitation was mild to moderate in 2 cases. Aortic arch descending angiography confirmed that all patients had a windowed PDA with a diameter of 4.6 to 14.5 mm, with a mean of (6.74±1.38) mm.
The right femoral vein was punctured under local or general anesthesia and injected with heparin 100 U/kg. After routine right heart catheterization, the right femoral artery was punctured and a 5F or 6F pigtail catheter was fed for lateral imaging of the descending aortic arch to understand the size, morphology, and position of the arterial duct relative to the anterior tracheal wall, and to measure its diameter. A right heart catheter with an exchange guidewire is first used to try to pass through the arterial duct into the descending aorta via the pulmonary artery, and after success, the stiffened exchange guidewire is replaced to the descending aorta.
If the guidewire is difficult to pass through the arterial catheter, the right heart catheter with a 260 cm mudskipper guidewire is sent to the pulmonary artery via the aortic end, and then the femoral vein is inserted into the capsule to the pulmonary artery and the tip of the capsule is pulled out of the body to establish a track, and the delivery device is sent along the guidewire to the descending aorta.
Release the blocker fixation disc first, retract the delivery sheath together, and when the fixation disc covers the aortic side of the arterial conduit, retract the delivery sheath that opens the waist of the blocker, fluoroscopy shows the waist of the blocker at the arterial conduit, and there is a more obvious pressure trace, after that, rely on the blocker delivery system to give a certain top force for 10~15 min, and wait for the blocker to harden and “coagulate After “coagulation”, repeat the lateral imaging of the descending aortic arch, and when there is no residual shunt or a very small amount of shunt (non-high-velocity flow), release the blocker, pull out the catheter, and put pressure on the puncture site to stop the bleeding and then dress it.
The blocking device was selected according to the diameter of the arterial catheter, and the domestic blocking device (produced by Beijing Huaji Shengjie Technology Co., Ltd.) was selected according to the principle that the measured diameter was 4~6 mm or larger.
The criteria for successful blocking were: the arterial catheter was completely blocked, there was no or only a small amount of residual shunt (non-high-speed flow), the blocker was fixed in position, in good shape, without dislodgement and displacement, no systolic pressure difference between the left pulmonary artery and main pulmonary artery and ascending aorta and descending aorta was measured, no intervention-related complications occurred, and the heart murmur was reduced or disappeared, which proved the successful blocking and the blocker could be released.
Postoperatively, routine antibiotics were administered intravenously for 3 days to prevent the occurrence of infection. Follow-up echocardiography, X-ray chest radiograph and ECG were performed at 72 h, 1 month, 3 months, 6 months and 1 year after the operation to understand the position, shape and presence of residual shunt of the blocker, changes in heart chamber size, pulmonary artery blood flow and complications.
Results
In 25 patients, 24 cases were successfully blocked, with a success rate of 96%; in one case, the angiography showed that the diameter of the window-type catheter was about 14.5 mm, and the lumbar indentation was not obvious after the 20/22 mm blocker was placed, and it was easy to fall off with slight pushing and pulling, so the treatment was abandoned.
The mean pulmonary artery pressure was (51.9±15.6) mmHg (1 mmHg=0.133 kPa) measured intraoperatively by transcatheter catheterization, and the mean pulmonary artery pressure was (32.2±9.6) mmHg immediately after blocking, which was significantly lower than that before blocking (P<0.05)< a="">[T1] .
There were 18 cases without residual shunt immediately after 15 min postoperative contrast and 6 cases with trace or small amount of residual shunt. The residual shunt was observed by color Doppler in the short-axis view of the great vessels and the long-axis view of the main pulmonary artery by echocardiography, and the residual shunt disappeared in 2 cases 72 h after surgery, in 3 cases within 1 month after surgery, and in 1 case within 3 months after surgery.
At 3 months after surgery, both left and right ventricular end-diastolic volumes were smaller than before surgery by echocardiography: (91.4±22.5)ml versus (116.3±30.4)ml, (51.6±11.2)ml versus (65.6±16.1)ml, P<0.05. Among the 3 cases with mild to moderate mitral regurgitation, 2 cases had completely disappeared at 3 months after surgery, and 1 case had only mild regurgitation. In 5 patients with combined mild to moderate tricuspid regurgitation, 2 had completely disappeared, 2 had only mild regurgitation, and 1 still had moderate regurgitation 3 months after surgery; in 2 patients with combined mild to moderate aortic regurgitation, 1 had completely disappeared and 1 had mild regurgitation 3 months after surgery< span="">.
Radiographs of all patients showed varying degrees of reduction in pulmonary blood and varying degrees of reduction in cardiothoracic proportions.
None of the patients had intraoperative or postoperative complications such as embolism, hemorrhage, hemolysis, pericardial compression, fatal arrhythmia, dislodgement of the blocker, displacement and vascular complications such as hematoma, pseudoaneurysm and arteriovenous fistula.
Discussion
Interventional treatment of PDA with the Amplatzer blocker has achieved great success and is now the treatment of choice for PDA. A domestic data set shows that this technique has a success rate of 98.1%, a complication rate of 2.0%, and a morbidity and mortality rate of 0.06% .
The hemodynamic changes in PDA are mainly due to the pulmonary artery receiving dual blood from both the right ventricle and the aorta, which increases the blood flow in the pulmonary circulation and returns to the left heart system via the pulmonary circulation to overload the left ventricle with volume. As the disease progresses, enlargement of the left and right heart chambers, increased pulmonary artery pressure, and even heart failure and pulmonary hypertension occur one after another, so early radical treatment is clinically advocated. after PDA interventional occlusion, the anatomical malformation and abnormal hemodynamic conditions are corrected, which inevitably have favorable effects on cardiac function.
Our results showed that the pulmonary artery pressure decreased immediately after PDA blocking, and the volume of both the left and right ventricles decreased 3 months after the procedure compared with that before blocking, suggesting that timely blocking intervention can reverse the above pathophysiological process and improve the left and right ventricular function continuously and effectively.
For windowed PDA remains a difficult area for interventional treatment. The results of this group show that interventional treatment of windowed PDA still has a high success rate as long as the indication for the procedure is strictly controlled and the appropriate size of the blocker is selected. Our experience is that a strict preoperative echocardiographic examination must be performed and the maximum diameter must not exceed 15 mm;
Even if the image shows a clear “waist” sign after the blocker is placed, the NiTi wire is easily deformed and less hard at room temperature (around 25°C) and below, and when it reaches a certain temperature (around 32°C) or above, it will return to its original preformed shape, and the hardness increases at this time. Therefore, the blocker will start to be soft under human blood temperature, and the incidence of blocker dislodgement will increase significantly when the blocker is released.
If we can rely on the blocker delivery system to give a certain top force to the blocker for 10~15 min after the blocker is placed, and then perform the imaging examination after the blocker has hardened and “solidified”, and then release the blocker, the success rate of the procedure can be significantly increased.