Calcification Alone Should Not Deter Percutaneous Mitral Commissurotomy for Rheumatic Stenosis

Download this article's Factoid (PDF & PPT for Gold Subscribers)

Percutaneous mitral commissurotomy (PMC) may be used as ‘first-line treatment’ for rheumatic mitral stenosis in patients with calcified valves, researchers propose in a study based on 20-year follow-up published April 29, 2014, ahead of print in Circulation: Cardiovascular Interventions. Differences in survival and functional outcome largely depend on immediate results and baseline characteristics apart from calcium, they say.

Both European and US guidelines deem PMC reasonable for patients with stenosis and moderate calcification, though the recommendation is listed as class IIa.

Benard Iung, MD, and colleagues at Bichat Hospital (Paris, France), reviewed outcomes up to 20 years after PMC in 1,024 patients treated for rheumatic mitral stenosis between 1986 and 1995. Among them, 314 patients (30.7%) had calcified valves—defined as group 3 by Cormier classification using fluoroscopy. At a median duration of 122 months (IQR 54-189), follow-up was complete for 92% of the calcified group and 89% of the noncalcified group.

Multiple Factors Account for Poor Results

At baseline, almost all measured patient and disease characteristics were worse in the calcified group. More severe calcification, as graded on a scale of 1 to 4 by 2 observers, rose in parallel with higher risk characteristics.

In-hospital death after PMC occurred in 4 patients with calcified valves (1.3%) but in none with noncalcified valves (P < .009). Rates of severe traumatic mitral regurgitation and embolism with sequelae were similar irrespective of calcification. Good immediate results (defined as final valve area ≥ 1.5 cm² and mitral regurgitation ≤ 2/4) were less common in the calcified group (80%) than in the noncalcified group (93%; P < .001).

On multivariable analysis, several factors predicted poor immediate results for patients with calcified valves (table 1).

Table 1. Predictors of Poor Immediate Results in Patients with Calcified Valves

At 20 years, overall survival was 50 ± 6% in the calcified group vs 81 ± 2% in the noncalcified group. Good functional results (defined as NYHA class I or II and survival without cardiovascular death or mitral reintervention) were seen in 12 ± 3% vs 38 ± 2% (P < .0001 for both).

After propensity matching accounted for differences in baseline characteristics, however, long-term survival was similar despite valve calcification. The calcified group continued to see worse functional results, though the disparity was smaller.

On multivariable analysis, several factors predicted poor late functional results in patients who initially had good immediate results after PMC (table 2).

Table 2. Predictors of Poor Late Functional Results After Good Immediate Outcome in Calcified Valves

“This study, reporting the longest follow-up after PMC in patients with calcified valves, shows that calcific [mitral stenosis] is associated with [worse] clinical characteristics that account for lower late survival rates,” the researchers conclude. “Therapeutic indications should be individualized according to age, symptoms, and rhythm. More importantly, the present findings allow for further refinement of the management strategy [based on severity of calcification].”

Approximately one-quarter of patients still derive a functional benefit from PMC after 15 years, they point out, indicating that the procedure “can be used as a first-line treatment.”

However, Dr. Iung and colleagues advise, “Patients with a high final gradient [after PMC] should be carefully followed up to allow for timely surgery.”

Bouleti C, Iung B, Himbert D, et al. Relationship between valve calcification and long-term results of percutaneous mitral commissurotomy for rheumatic mitral stenosis. Circ Cardiovas Interv. 2014;Epub ahead of print.

Related Stories:

• Percutaneous Mitral Commissurotomy Effective Even in Calcified Valves
• Percutaneous Mitral Commissurotomy Shows Long-term Success, Even with Reintervention
• Groups Outline Key Issues for Dissemination of Transcatheter Mitral Valve Therapies