Methods

Between 1973 and 2012, 1,014 patients with TOF underwent 1,212 surgeries at Mayo Clinic (Rochester, Minnesota). Of those, 362 had a PVR. All PVR were performed at our institution, but some initial repairs were undertaken elsewhere. Only patients who underwent a first-time PVR after TOF repair were selected. Patients with pulmonary atresia, TOF with absent pulmonary valve, patients with a concomitant atrioventricular canal defect, and patients who refused research authorization were excluded. Overall, 278 patients met the inclusion criteria to be studied. The study was approved by the Mayo Clinic Institutional Review Board.

Medical history and perioperative and postoperative follow-up data were collected using all available medical records. Baseline demographic characteristics were collected and are listed in Table 1 . The date of preoperative evaluation, including echocardiography, was defined as the most recent evaluation before PVR and was at most 3 years removed. Left ventricular (LV) ejection fraction and RV pressure were collected as continuous variables, whereas LV and RV size, RV function, and tricuspid and pulmonary valve regurgitation were collected as qualitative categorical variables.

Data regarding the surgical procedure were also collected ( Table 2 ). The type of valve or conduit used for the PVR was grouped into 4 categories:

• •
  

  Porcine: Carpentier-Edwards porcine (n = 82), Mosaic porcine (n = 21), St. Jude bio porcine (n = 45), Hancock porcine (n = 62), and Tascon porcine (n = 1).

  
  
• •
  

  Pericardial: Carpentier-Edwards pericardial (n = 29) and Ionescu-Shiley pericardial (n = 8).

  
  
• •
  

  Homograft: cryopreserved pulmonary homograft (n = 23) and aortic homograft (n = 4).

  
  
• •
  

  Mechanical (n = 3).

The choice of valve was based on the preference of the surgeon. Table 2 also summarizes the associated procedures performed during the PVR.

All patients who have undergone cardiac surgery at Mayo Clinic are sent follow-up surveys on a routine scheduled basis. In addition, the Social Security Death Index was reviewed. The primary outcome was death of any cause. Operative mortality was defined as death that occurred within the first month of surgery or before discharge in those hospitalized for >1 month. The secondary outcome was defined as the need of pulmonary valve reintervention, either surgical or transcatheter pulmonary valve re-replacement. The mean duration of follow-up was 7.3 ± 6.8 years (range <1 to 34 years) and was available for 97.5% of patients. Survival was compared with an age- and gender-matched US population. To assess the potential impact of surgical era on survival, the cohort was divided in the period between 1973 and 1999 (n = 89) and the period between 2000 and 2012 (n = 189), the latter coinciding with a marked increase in annual surgical volumes of PVR at our institution.

One of the objectives of the study was to evaluate the indications for tricuspid valve repair or replacement at the time of PVR. Statistical analysis was based on tricuspid intervention or lack thereof, in terms of survival, reintervention, degree of tricuspid regurgitation, and RV remodeling during follow-up. The vast majority of patients had some degree of tricuspid regurgitation before surgery ( Table 1 ). All patients with more than moderate tricuspid regurgitation underwent intervention on the tricuspid valve. Because of this, there was no nonintervention group to be compared with and, thus, were not included in the subanalysis. Therefore, only patients with moderate tricuspid regurgitation were analyzed.

Echocardiographic analyses were based on the comparison between preoperative and postoperative right and LV size and function. A total of 263 patients underwent 1,164 echocardiographic examinations during postoperative follow-up. To perform the pre- versus postanalysis, we selected 3 time points: echo before discharge, last echo done at 3 to 18 months of follow-up, and last echo done after 18 months of follow-up (except for patients requiring reintervention in which last echo before reintervention was the one evaluated). Improvement in echo parameters was defined as any of the following: (1) decrease in RV size, (2) improvement in RV function, and (3) >5% increase in LV ejection fraction (%) (e.g., 50% to 55%).

Functional class was defined in terms of the New York Heart Association (NYHA) classification. A comparison was made between preoperative and postoperative functional class. Two time points, early and late follow-up, were selected. Early follow-up was defined as the first visit after discharge. Late follow-up was defined as the last visit available, except for patients requiring reintervention in which last visit before reintervention was the one evaluated.

Descriptive statistics are reported as proportions for discrete data and means and SDs for continuous data, except for variables that are not normally distributed in which case median and range were used. Survival and event-free times were analyzed using Kaplan-Meier method with 95% confidence intervals (CIs). Survival curves were compared by the log-rank test. Univariate and stepwise multivariate analyses were used to determine risk factors for reintervention, need of cardiac surgery, and death. Only variables that were found to be statistically significant (p <0.05) according to univariate analysis were then included in the multivariate analyses. Comparisons of patient and test data before and after surgery were performed using t test pairs or Wilcoxon test accordingly.

Results

A summary of the medical history and preoperative conditions are listed in Table 1 . Mean age at PVR was 31.4 ± 16.4 years, with 24% of patients under 18 years.

A summary of the surgical procedures is listed in Table 2 . The mean pulmonary valve or conduit size implanted was 26.8 ± 2.9 mm (range 19 to 33). Homografts were significantly smaller than others, with a mean size of 24 ± 2 mm (range 21 to 30), p <0.001. Table 3 details PVR size used in our cohort; older and larger patients required bigger valves, p <0.001. Aortic cross-clamp was used in 139 patients (50% of patients), for a mean time of 42 ± 35 minutes (range 2 to 174 minutes). Cardiopulmonary bypass was used in all patients for a mean time of 91 ± 56 minutes (range 17 to 333 minutes).

The low operative mortality in our cohort (n = 4, 1.4%) precluded an independent survival analysis; therefore, those patients were included in the overall survival analysis. Two of the 4 operative deaths were related to anomalous coronary arteries that were injured during surgery. Late mortality was cardiac related in 11 of 31 patients, with 6 of 11 being sudden cardiac death. Five of 31 deaths were noncardiac related, whereas the remainder are unknown.

Overall, death occurred in 35 patients at a mean age of 43 ± 18 years and a mean time of 7.4 ± 8 years after the PVR. The Kaplan-Meier curve for survival of our cohort compared with an age- and gender-matched US population is shown in Figure 1 . Early survival was excellent with 96.8% (CI 94.6 to 99.0) and 92.6% (CI 89.2 to 96.2) at 1 and 5 years of follow-up, respectively. Long-term survival was acceptable with 83.1% (CI 77.2 to 89.4) and 79.6% (CI 72.4 to 87.5) at 10 and 15 years of follow-up, respectively. Survival in our cohort was significantly worse than the matched US population. Survival was better in patients with NYHA functional class I to II at the time of surgery, with 89.1% (CI 82.2 to 96.7) survival at 15 years compared with 67.6% (CI 55.8 to 81.9) in the NYHA III to IV symptom group (p = 0.006).

Kaplan-Meier estimates of survival (A) comparing our cohort ( solid line ) with an age- and gender-matched US population ( dashed line )—the number at risk belongs to our cohort, (B) by type of valve that was used, and (C) by era of surgery.

Survival was significantly better in patients with porcine or homograft types of valve or conduit than those with pericardial valves, with 83.4% (CI 75.4 to 92.3) and 86.5% (CI 73.5 to 100.0) versus 43.6% (CI 20.8 to 91.1) alive at 15 years of follow-up (p = 0.008) ( Figure 1 ). Only 3 patients had a mechanical valve implanted and were not included in either the survival or univariate analyses; 1 patient died 6 months after the PVR. There were no differences in survival by surgical era ( Figure 1 ).

Univariate and multivariate predictors for mortality are detailed in Table 4 . The independent risk factors that were statistically significant in the multivariate model were (1) older age at initial TOF repair, (2) 3 or more previous cardiac surgeries, (3) advanced functional class at the time of PVR, and (4) large body surface area at the time of PVR.

Table 4

Univariate and multivariate analysis for mortality and reintervention

Variables	Mortality				Reintervention
	HR	95% CI		p Value	HR	95% CI		p Value
Univariate analysis
Female	0.8	0.4	1.5	0.4	1.1	0.5	2.4	0.8
NYHA III–IV	2.7	1.3	5.8	0.009	0.9	0.4	2.3	0.9
Type of valve
Porcine	Reference
Pericardial	2.9	1.3	6.7	0.01	0.7	0.2	3.1	0.7
Homograft	0.6	0.2	1.9	0.3	0.4	0.1	1.4	0.2
QRS pre ≥ 180 msec	1.2	0.5	3.1	0.7	0.6	0.2	2.1	0.4
Number of previous surgeries
1	Reference
2	1.5	0.7	3.6	0.3	1.2	0.5	2.9	0.8
3 or more	2.9	1.1	7.4	0.03	1.2	0.4	3.8	0.8
Pacemaker	2.4	0.8	6.8	0.1	1.4	0.3	5.8	0.7
Transannular patch	1.1	0.6	2.2	0.8	1.6	0.7	3.7	0.3
Concomitant procedure	2.4	1.0	6.3	0.07	0.9	0.4	2.0	0.7
Older age at palliation (Δ 5 years)	1.3	1.0	1.5	0.03	0.8	0.5	1.5	0.6
Older age at repair (Δ 5 years)	1.2	1.1	1.3	<0.001	0.6	0.4	1.0	0.06
Older age at surgery (Δ 5 years)	1.2	1.1	1.3	0.001	0.7	0.6	0.9	<0.001
BSA	1.9	1.4	2.5	<0.001	0.3	0.1	0.6	0.001
Years from repair to surgery	1.0	1.0	1.0	0.6	0.9	0.9	1.0	<0.001
Valve size	1.1	0.9	1.2	0.4	0.8	0.7	0.9	<0.001
RV size ≥ moderate dilation	1.9	0.3	14.0	0.6	1.0	0.1	7.3	1.0
RV function ≥ moderate dysfunction	1.7	0.7	4.2	0.3	0.4	0.1	1.3	0.1
TR ≥ moderate	2.7	1.1	6.6	0.03	1.4	0.5	4.1	0.6
LVEF (Δ 5%)	0.9	0.7	1.0	0.1	1.3	0.9	1.7	0.1
LV enlargement	3.5	1.6	7.6	0.002	0.9	0.2	3.9	0.9
RV pressure (Δ 10 mm Hg)	1.0	0.8	1.3	1.0	0.7	0.5	1.0	0.08
Multivariate analysis
Older age at repair (Δ 5 years)	1.2	1.0	1.3	0.01
3 or more previous surgeries	1.9	1.1	3.1	0.02
NYHA III-IV	2.7	1.2	6.1	0.02
BSA	1.9	1.4	2.5	<0.001
Older age at surgery (Δ 5 years)					0.7	0.6	0.9	<0.001

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