Vena caval obstruction (VCO) is a common complication after vascular manipulation for congenital heart disease. Long-term efficacy of stent therapy for relief of VCO and long-term stent patency with and without intrastent transvenous pacing leads (TPLs) is not well described. This was a retrospective review of patients treated for VCO, including those who received intrastent TPLs, between 1995 and 2012. Patient demographics, diagnoses, vascular pressure gradients, and vessel diameters were analyzed. Forty-one patients (mean age 23.5 ± 10.3 years) with and without congenital heart disease underwent stent implantation, 26 of whom also received intrastent TPLs. Short-term stent implantation success in relieving obstructions was 93%. Poststent vascular pressure gradients and percentage vascular narrowing significantly improved (from 6.2 ± 4.5 to 1.1 ± 1.6 mm Hg and from 63.1 ± 19.5% to 18.0 ± 17.1%, respectively, p <0.05). On follow-up in 38 of 41 patients from 0.2 to 18 years (median 6.0), all survived; 6 (14%) required stent reintervention. Freedom from reintervention was 87% at 15 years. Patients with short-term procedural failure were at higher risk for stent reintervention. Among 27 patients with intrastent TPLs, freedom from reintervention was 96%. In 26 patients with follow-up catheterization, intrastent intimal proliferation was not significantly associated with TPL but was higher in the superior vena cava–innominate vein junction compared with other stent locations (p <0.05). In conclusion, stent therapy for VCO can be successfully and safely performed with good long-term results. Pre–pacing lead stent placement for VCO is effective in allowing TPL placement with encouraging long-term patency.
Vena caval obstruction (VCO) has been increasingly recognized in children and adults, after surgical repair of certain congenital heart defects and vascular manipulation such as extracorporeal membrane oxygenation (cannulation) and ventriculoatrial shunting for noncardiac patients. Stent placement has evolved as a widely accepted transcatheter approach for symptomatic VCO. Furthermore, stent placement can relieve vascular obstructions, allowing transvenous pacing lead (TPL) implantation. A few previous studies have shown short-term efficacy in preemptive stent placement in patients with evidence of partial or complete VCO after intra-atrial Mustard baffle repair for D-transposition of the great arteries (d-TGA), to permit intrastent TPL placement. However, the long-term patency of vascular stents in the presence of inserted TPLs remains unknown. The primary aims of this study were to assess the immediate and long-term outcomes of stent patency for VCO and to evaluate the long-term interaction and patency of stents with TPLs in children and adults with and without congenital heart disease (CHD) in a single institution.
Methods
This was a retrospective study approved by the Institutional Review Board of Wayne State University School of Medicine. Patients who underwent transcatheter stent placement for VCO from 1995 to 2012 were included. The catheterization reports and medical records for procedural and follow-up data were reviewed in all patients. The degree of stenosis was quantified on the basis of hemodynamic and angiographic data. The narrowest and referenced normal proximal vascular diameters seen on venography were manually measured before and after intervention. The mean vascular pressure gradients between pre- and poststenotic sites were collected. Significant or partial VCO was defined as stenosis (mean pressure gradient >4 mm Hg or vessel narrowing >50% compared with the normal proximal caliber) in the following venous structures: superior vena cava (SVC), SVC–right atrium (RA) junction, SVC–innominate vein junction, inferior vena cava (IVC), SVC–Mustard baffle, or IVC–Mustard baffle. Severe obstruction was defined as a mean gradient ≥10 mm Hg or vessel narrowing ≥75% compared with the normal proximal diameter. Immediate procedural success was defined as a resultant mean pressure gradient <4 mm Hg and vessel narrowing <50% before compared with after stent insertion. During the follow-up catheterizations, the severity of intrastent intimal proliferation was derived from the formula (narrowest intrastent internal diameter/stent diameter) × 100 ( Figure 1 ). Intrastent intimal proliferation >20% was considered significant in our study.
Cardiac catheterization was performed using standard techniques, including general anesthesia per institutional protocols. Venous access was obtained in the right internal jugular and/or femoral veins. After hemodynamic pressure evaluations, venography delineated the length and degree of any vascular obstruction. Before stent placement, antibiotic prophylaxis was given with adequate anticoagulation using intravenous heparin 75 to 100 U/kg, followed by serial doses to achieve activated clotting times >250 ms. Balloon-dilatable stents were placed in a standard fashion. The choice of stent type was based on each operator’s preference. A total of 49 stents were placed in 42 VCO locations. These included the Genesis XD (Cordis Corporation, Miami Lakes, Florida), n = 31 (63%); Palmaz P308 (Johnson & Johnson, New Brunswick, New Jersey), n = 13 (27%); Palmaz XL (Johnson & Johnson), n = 4 (8%); and CP stent (NuMED Inc., Hopkinton, New York), n = 1 (2%). Severe obstruction was found in 16 of 42 VCO locations (38%); 4 of these had complete obstruction. Before stent placement, 4 patients (10%) underwent balloon angioplasty for VCO.
Among patients with complete obstruction, vascular recanalization was first achieved using the stiff end of a guidewire (i.e., 0.018-inch Flex-T wire; Mallinckrodt Medical Inc., St. Louis, Missouri) and/or a transseptal needle system to bypass the obstruction ( Figure 2 ). A catheter or opened snare was placed in the distal segment of the occlusion as a target marker, ensuring the direction of recanalization. Stent placement was then performed after initial balloon angioplasty using a 4- to 6-mm-diameter balloon catheter. Stents were placed over a balloon with size approximating 100% of the reference vessel to achieve ≥80% to 90% (after stent recoil) of the reference vessel diameter using medium-pressure balloon catheters (maximum 6 to 8 atm). Aggressive stent and vessel dilation was not pursued by high-pressure or cutting balloon catheters. This was our strategy to obtain satisfactory improvement and avoid potential injury. After stent placement, aspirin once daily at 81 mg in adults and 4 mg/kg in children was prescribed for 6 months if patients were not already receiving antiplatelet or anticoagulation therapy.
TPLs were placed through the stents in 27 patients (63%), 23 in the SVC–Mustard intra-atrial baffle and 4 in the SVC-RA or SVC–innominate vein junction. Of these, 2 patients received 3 and 16 patients received 2 leads, while 9 patients had only 1 lead implanted through the stents placed at various VCO locations. Lead placement was performed concurrently at the initial stent placement in 19 patients. New or additional lead placement was performed at the subsequent catheterizations in 12 patients. Lead choice was left to the discretion of the implanting electrophysiologist and included both pacemaker and implantable cardioverter-defibrillator (ICD) leads from various companies. These ranged in diameter from 4.1Fr to 8.6Fr and had various silicone and polyurethane insulations.
Statistical analysis was performed using SPSS version 22.0 (SPSS, Inc., Chicago, Illinois). Continuous variables are reported as mean ± SD or as medians with ranges, and nominal variables are reported as number (percentage). Paired and independent-samples Student’s t test, analysis of variance, and chi-square tests were used to compare demographic, hemodynamic, and angiographic parameters between groups on the basis of variable types. The Kaplan-Meier product-limit method and log-rank test were used to analyze freedom from reintervention and significant intrastent intimal proliferation to examine the association of potential variables. A p value <0.05 was considered to indicate statistical significance.
Results
Forty-one patients (mean age 23.5 ± 10.3 years) were identified who underwent stent placement for VCO in 42 venous locations. The median interval from the initial vascular manipulation or cardiac surgery to VCO stent implantation was 21.7 years (range 11 months to 39.8 years). Figure 3 illustrates the diagnoses with their indications for catheterization. The most prevalent CHD diagnosis was repaired d-TGA with the Mustard intra-atrial baffle, seen in 31 patients (75%), followed by other CHD in 4 (10%) and previous vascular manipulations in 6 (15%). The primary indication for the catheterization was an electrophysiologic evaluation before TPL implantation in 28 patients (68%). Only 4 patients (10%) had venous obstructive symptoms such as SVC syndrome or ascites. The location of VCO included the SVC–Mustard baffle in 29, IVC–Mustard baffle in 3, SVC–innominate vein junction in 4, SVC-RA junction in 4, SVC itself in 1, and IVC in 1 patient. One patient with d-TGA underwent dual stent placement in the SVC– and IVC–Mustard intra-atrial baffles. A total of 49 stents were placed in the 42 VCO locations. One patient received 3 stents, and 5 patients received 2 stents for each VCO location.
At the initial stent placement, acute procedural success, as defined earlier, was 93%. The mean vascular peak pressure gradient and percentage vessel narrowing significantly improved (p <0.05; Table 1 ). There were no procedural deaths or vessel injuries. There was a stent migration in 1 patient. A 26-year-old patient with d-TGA who had undergone the Mustard procedure underwent stent placement for VCO in the SVC–Mustard baffle. The stent migrated inferiorly and was repositioned in the IVC. A second stent was placed in the SVC–Mustard baffle successfully. Table 2 shows the demographic data and acute outcomes between the severe (n = 16) and partial (n = 26) VCO groups. Prestent gradients across the VCO and percentage narrowing were significantly higher in the severe obstruction group. This group was also less likely to achieve acute procedural success than the partial obstruction group (81% vs 100%, p <0.05). Although the vascular peak pressure gradient and percentage vessel narrowing improved significantly with stent placement in the 2 groups, the poststent pressure gradient remained significantly higher in the severe compared with the partial VCO group (p <0.05). Acute procedural failure was noted in 3 of 42 venous locations. Of these, 2 locations had near complete venous obstruction. Despite successful stent placement, the 2 locations had residual discrete stenosis resistant to angioplasty using medium-pressure balloon catheters. The remaining patient had a residual pressure gradient of 5 mm Hg due to a relatively small baffle despite satisfactory angiographic results.
| Variable | Pre-stent (n=42) | Post-stent (n=42) | p value ∗ |
|---|---|---|---|
| Peak pressure gradient (mmHg) | 6.2 ± 4.5 | 1.1 ± 1.6 | < 0.05 |
| pre-stenotic pressure (mmHg) | 12.9 ± 5.4 | 8.7 ± 5.1 | < 0.05 |
| post-stenotic pressure (mmHg) | 6.0 ± 3.7 | 7.7 ± 4.2 | < 0.05 |
| Narrowing (%) | 63.1 ± 19.5 | 18.0 ± 17.1 | < 0.05 |
| Narrowest site (mm) | 6.0 ± 3.7 | 13.3 ± 2.9 | < 0.05 |
| Normal vessel (mm) | 16.4 ± 4.7 | — | — |
∗ p value is for comparing values between initial post-stent and follow-up.
| Variable | Vena Caval Obstruction | ||
|---|---|---|---|
| Severe (n=16) | Partial (n=26) | p value | |
| Age (year) | 20.6 ± 12.1 | 24.9 ± 9.2 | NS |
| Weight (kg) | 54.5 ± 26.3 | 70.9 ± 23.2 | < 0.05 |
| Non CHD diagnosis | 21% (3/14) | 11% (3/28) | NS |
| D-Transposition of the great arteries | 64% (9/14) | 79% (22/28) | NS |
| Duration between surgery and stent (year) | 19.3 ± 13.0 | 23.0 ± 9.4 | NS |
| Acute outcome | |||
| Acute success | 81% (13/16) | 100% (26/26) | < 0.05 |
| Pre-stent peak pressure gradient (mmHg) | 10.2 ± 3.7 | 3.7 ± 2.5 | < 0.05 |
| Post-stent peak pressure gradient (mmHg) | 2.1 ± 1.9 | 0.4 ± 0.7 | < 0.05 |
| Pre-stent narrowing (%) | 83.2 ± 14.8 | 51.3 ± 10.8 | < 0.05 |
| Post-stent narrowing (%) | 23.8 ± 20.2 | 14.4 ± 14.1 | NS |
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