Nicholas Collins

Covered stents in the management of coarctation of the aorta in the adult: Initial results and 1-year angiographic and hemodynamic follow-up

BACKGROUND The purpose of this study was to determine the safety and efficacy of the Cheatham Platinum covered stent in adults with coarctation of the aorta. METHODS Adults with native coarctations (n=14); previous coarctation surgery (n=4), stenting (n=1) or both surgery and endovascular therapy (n=3) underwent percutaneous intervention with a covered stent. Indications for stenting in those with previous intervention were recurrent coarctation (n=4), aneurysm formation at the site of previous intervention (n=2) or both recurrent coarctation and aneurysm formation (n=2). RESULTS Twenty-three covered stents were placed in 22 patients (mean age 39+/-14 years, n=11 males). Successful device deployment was achieved in all patients, although one patient required a second covered stent for aortic wall rupture. Peak systolic gradient across the coarctation site decreased from 29+/-17 to 3+/-5 mm Hg (p<0.001) immediately following implant and this was maintained (6+/-9 mm Hg, p=0.001) at invasive assessment, 12 months after the initial procedure. Right arm systolic blood pressure significantly declined (p=0.02), as did the number of antihypertensive medications per patient (p=0.03). At angiographic follow-up, post-stenotic dilatation of the aorta decreased from 32+/-8 mm to 30+/-8 mm (p=0.001), however, no stent recoil was observed. CONCLUSIONS Covered stents are safe, durable and efficacious in the management of coarctation of the aorta. Angiography and hemodynamic assessment is an effective method of screening for recurrent coarctation, and arch and vascular complications after stenting in adults.

Percutaneous coronary artery fistula closurein adults: Technical and procedural aspects

Coronary artery fistulae (CAF) are an uncommon congenital anomaly characterized by an abnormal connection between the coronary arteries and cardiac chambers or vessels without traversing the usual capillary network. CAF are associated with a number of well‐described symptomatic sequelae, which may necessitate treatment. With a tendency for symptoms to develop over time, symptomatic CAF may present for the first time in adulthood, with limited data existing on the technical aspects related to transcatheter fistula closure in adults.

Long-Term Outcomes After Percutaneous Coronary Intervention of Bifurcation Narrowings

The optimal approach to percutaneous coronary intervention (PCI) of bifurcation lesions remains unclear, reflecting lack of long-term follow-up and heterogeneity of lesions encountered. We evaluated the long-term outcome of patients undergoing bifurcation PCI followed in the prospective bifurcation registry at the University Health Network, Toronto, Ontario, Canada. Of 526 patients undergoing bifurcation PCI between November 2003 and March 2005, most (n = 406) were treated by main vessel stenting only (n = 266) or crush/culotte stenting (n = 140). After median follow-up of 26.5 months, major adverse cardiac events (MACEs) and Canadian Cardiovascular Society class > or =2 angina occurred in 28.5% and 22.3% of patients in these groups, respectively (p = 0.190), whereas MACE rates were 20.8% for main vessel stenting and 18.7% for crush/culotte stenting (p = 0.670). A low bifurcation angle was associated with better outcomes in the crush/culotte group but had no effect on outcome of patients treated with main vessel stenting only. Use of crush/culotte techniques independently predicted freedom from MACEs or Canadian Cardiovascular Society class > or =2 angina compared with main vessel stenting only (odds ratio 0.55, 95% confidence interval 0.32 to 0.94, p = 0.029). In conclusion, the use of crush/culotte stenting is safe, with efficacy and MACE rates being similar to main vessel stenting alone. Our observations regarding the effect of lesion characteristics such as bifurcation angle and extent of side branch disease on outcome underscore the need for randomized trials that are inclusive of patients with complex side branch disease.

A modified balloon crush approach improves side branch access and side branch stent apposition during crush stenting of coronary bifurcation lesions.

Objectives: Despite the advent of drug eluting stents and newer interventional techniques designed to treat the main vessel and side branch in bifurcation stenoses, optimal treatment of the side branch remains problematic. We aimed to assess the feasibility of a modified balloon crush technique for percutaneous treatment of coronary bifurcation stenoses. Background: Use of the crush technique in bifurcation stenoses remains limited by access to the side branch after main vessel stent deployment, as well as limitations of side branch stent deployment. The modified balloon crush technique aims to improve side branch access and stent apposition. Methods: The modified balloon crush is similar to the previously described balloon crush technique. Following side branch stent deployment, a balloon positioned in the main vessel is deployed to crush the proximal side branch stent. A guide wire is then placed into the side branch with a subsequent high‐pressure balloon inflation at the side branch ostium. This opens the stent struts at the ostium of the side branch, facilitating future passage of the guide wire following main vessel stent deployment, prior to kissing balloon inflation. Results: We performed this modification of the crush technique safely in 10 patients. We were successful in obtaining side branch access in nine of ten patients following initial main vessel stent deployment. In the only failure, there was a 90° angle between the main vessel and side branch. Conclusions: The modified balloon crush technique can be safely performed, while optimizing side branch access and side branch stent apposition.

Prevalence and Determinants of Anemia in Adults With Complex Congenital Heart Disease and Ventricular Dysfunction (Subaortic Right Ventricle and Single Ventricle Physiology)

Anemia is well recognized as a marker of poor prognosis in patients with acquired heart disease and heart failure. Adults with complex congenital heart disease and ventricular dysfunction (subaortic right ventricle or single-ventricle physiology) represent a different population, because they are typically much younger and have less co-morbidity compared with patients with acquired forms of heart disease. The purpose of this study was to evaluate the prevalence and determinants of anemia in this population. Baseline hemoglobin levels were recorded at the time of the initial clinic visit, and final hemoglobin levels were those recorded before death or transplantation or at study completion. Anemia was defined as hemoglobin <135 g/L in men and <120 g/L in women. One hundred sixty-seven patients (100 men, mean age 34 +/- 8 years, mean ejection fraction 35 +/- 9%) were included, 66 with atrial switch operations, 42 with congenitally corrected transposition of the great arteries, and 59 with Fontan physiology. The mean hemoglobin level at baseline was 149 +/- 22 g/L and at follow-up was 139 +/- 29 g/L. The overall prevalence of anemia was 29% at completion. Hyponatremia, decreased renal function, and the use of warfarin were independent predictors of anemia. In conclusion, anemia is common in patients with complex congenital heart disease and ventricular dysfunction, in particular those with Fontan physiology.

Role of routine radial artery access during aortic coarctation interventions

We read with interest the review article by Dr. Golden and Dr. Hillenbrand entitled Coarctation of the aorta: stenting in children and adults [1]. We agree with the conclusion that in adult sized adolescents and adult patients, stent deployment is the treatment of choice for coarctation assuming appropriate anatomy and lack of other indications for cardiovascular surgery. The authors appropriately emphasize the importance of awareness of the potential for complications and the need for early identification and treatment when such events occur. As such, we routinely use radial artery access in adult patients undergoing aortic coarctation stenting. This allows prompt recognition of complications, as well as immediate hemodynamic assessment during the procedure. Radial artery access is a simple and safe technique that compliments various diagnostic and therapeutic elements of aortic coarctation stenting. Our current practice is to perform aortic stenting under general anesthesia, each patient having access from both the femoral (8 French) and radial artery (6 French) (Fig. 1). After radial artery sheath placement, a combination of intraarterial verapamil (1 mg) and nitroglycerin (100 mcg) is given in to the sheath to prevent spasm. A 6 Fr. pigtail catheter is positioned from the radial artery into the descending aorta proximal to the coarctation. The coarctation site is then crossed using an 8 Fr. Gensini (Cordis/Johnson and Johnson, Warren, NJ) catheter from the femoral artery. We have found that simultaneous radial artery monitoring confers several advantages. In preparing for stent delivery, it allows for accurate assessment of the gradient across the coarctation site. Performing aortography through the pigtail catheter from radial artery is useful in defining the position of the stent before deployment and clarifying the origin of the left subclavian during implantation. Continuous invasive monitoring during and immediately after stent deployment permits accurate assessment of systemic blood pressure, assisting prompt recognition of hemodynamic instability because of aortic disruption. During assessment of such complications, the radial artery access obviates the need for catheter exchange of the stent balloon after deployment and nullifies the associated delay in defining the origin of the instability. Additionally, in cases where crossing the coarctation site is difficult, an alternative method is exchanging the pigtail catheter from the radial artery with a 4 Fr. multipurpose catheter. This in turn allows placement of a 0.035@ extra stiff exchange guide wire, which can be advanced across the lesion. The wire can then be snared in the descending aorta and exteriorized through the right Fig. 1. Two pigtails can be seen: one in descending aorta through the femoral sheath; the other in the ascending aorta through the right radial artery.

Iatrogenic ST Elevation during Percutaneous Closure of a Coronary Artery Fistula

Coronary artery fistulae are an uncommon anomaly and, while frequently asymptomatic, may require interventional therapy. Transcatheter approaches for closure of coronary artery fistulae are now commonly used, with various methods of fistula occlusion described, including detachable coils. During a percutaneous procedure to occlude a symptomatic left anterior descending coronary artery to pulmonary artery fistula, the patient experienced chest discomfort with anterior ST segment elevation. We demonstrate an unusual, unique and striking ECG abnormality complicating the delivery of coils designed to occlude the fistula in the absence of coronary artery injury. The mechanisms of the procedural ECG changes are discussed, as are potential alternate diagnoses and associated therapy.Coronary artery fistulae are an uncommon anomaly and, while frequently asymptomatic, may require interventional therapy. Transcatheter approaches for closure of coronary artery fistulae are now commonly used, with various methods of fistula occlusion described, including detachable coils. During a percutaneous procedure to occlude a symptomatic left anterior descending coronary artery to pulmonary artery fistula, the patient experienced chest discomfort with anterior ST segment elevation. We demonstrate an unusual, unique and striking ECG abnormality complicating the delivery of coils designed to occlude the fistula in the absence of coronary artery injury. The mechanisms of the procedural ECG changes are discussed, as are potential alternate diagnoses and associated therapy.

Chronic pulmonary thromboembolism in a patient with a fontan circulation: percutaneous management.

Chronic pulmonary embolism is a common complication in patients with Fontan circulations. When anticoagulation is ineffective and surgery is contraindicated, percutaneous techniques may be considered. The authors report the first case of successful catheter intervention in a 30‐year‐old woman with a Fontan circulation who presented with NYHA class IV symptoms and chronic and complete obstruction of her left pulmonary artery.

Sheath stabilizing technique for balloon sizing of large atrial septal defects response to article by Dr. Zahid Amin entitled "Transcatheter closure of secundum atrial septal defects".

We read with interest the article by Dr. Amin regarding transcatheter closure of secundum atrial septal defects (ASD) [1]. We agree with his comments of the importance of balloon sizing of the defect and acknowledge the difficulties that may be encountered in patients with deficient rims, and those with large defects. A common cause of the inability to balloon size such defects is the lack of a stable position of the sizing balloon. While relying solely on echocardiographic measurements was suggested in such problematic cases, we feel additional methods of optimizing balloon sizing can be used. We describe a novel ‘‘sheath-stabilizing’’ technique that we have used in two cases where balloon sizing was difficult. The first patient was a 34-year-old woman with an ASD measuring 27 mm on transesophageal echocardiography (TEE), the second was a 32-year-old woman with a 20 mm defect on TEE. Both patients had evidence of right ventricular enlargement in the absence of significant pulmonary hypertension. As described in Dr. Amin’s article, we follow standard techniques for ASD closure. After the defect is crossed with an 8-Fr Gensini catheter, an Amplatzer exchange length wire (Cook, Bloomingtion IN) is advanced to the left upper pulmonary vein, and an AGA sizing balloon (AGA Medical, Golden Valley, MN) positioned across the defect. In both patients, a combination of the large size of the defect and insufficient rims did not allow a stable position of the balloon (Figs. 1 and 2). It would have been standard practice to abort the procedure, deem the defects unsuitable for percutaneous closure, or rely purely on echocardiographic measurement as recommended by Dr. Amin. In these cases we chose to attempt to stabilize the balloon. The proximal end (20 cm) of a 12-Fr AGA Fig. 1. LAO CRA View. The balloon has prolapsed from the defect and no waste is identified.