**6. Special considerations**

#### **6.1. LAA/LAA thrombus**

If the patient is clinically stable, BMV can be postponed for 3–6 months, while the patient receives intensive anticoagulation with an INR of 3–3.5. If repeated TEE shows that the clot has been completely resolved, BMV can be safely performed. If the thrombus persists, the patient should be referred for open mitral valvulotomy or MVR. If surgery is not a feasible option, BMV is not possible to be deferred, and the thrombus is small, fixed, and confined to the LAA, experienced operators might do BMV ensuing that the wire and balloon catheter are kept away from the LAA.

#### **6.2. Previous valvulotomy**

(Inoue vs. double balloon and metallic commissurotomy) [20, 32]. Unfavorable valve anatomy and inappropriate balloon sizing and inflation protocol predict the occurrence of severe MR after BMV, but their predictive value is not high and it can occur unpredictably in some patients with good morphologic features. Most patients need subsequent mitral valve surgery (mostly MVR) because severe MR is associated with the deterioration of functional status and poor outcomes. The timing of the surgery is determined by clinical tolerance, hemodynamic stability, mechanism of MR, and surgical risk. Most patients with severe MR can be managed conservatively and are subjected to mitral valve surgery on a scheduled basis. In a small number of patients who remain severely symptomatic despite initial medical therapy or who experience hemodynamic instability, or when the mechanical background of MR is severe and irreversible, urgent MVR should be planned. Patients with moderate MR can be often followed-up for a long period of time and some even experience a reduction in the severity of

A wide range of frequency has been reported (10–90%) depending on modality that has been used for detection [35, 36]. Most defects decrease in size or disappear over time and have no adverse effects [37]. Infrequently, the defect is large enough to cause significant left-to-right shunting, especially when there is a significant residual mitral valve gradient and, therefore, surgical repair should be performed along with mitral valve surgery. Percutaneous closure of post-BMV residual atrial septal defects has not been reported and seems to be unsuccessful. In rare circumstances, right-to-left shunting and subsequent paradoxical embolism might

Rarely, patients need emergent surgery because of the complications. The most frequent cause is hemopericardium unresponsive to pericardiocentesis, especially when it happens after septal dilation and LV perforation. In most patients, the surgery includes repair of the

If the patient is clinically stable, BMV can be postponed for 3–6 months, while the patient receives intensive anticoagulation with an INR of 3–3.5. If repeated TEE shows that the clot has been completely resolved, BMV can be safely performed. If the thrombus persists, the patient should be referred for open mitral valvulotomy or MVR. If surgery is not a feasible option, BMV is not possible to be deferred, and the thrombus is small, fixed, and confined to the LAA, experienced operators might do BMV ensuing that the wire and balloon catheter are kept away from the LAA.

tearing and MVR. Severe MR can also necessitate urgent surgery in some patients.

happen in patients with significant pulmonary hypertension.

MR over time [33, 34].

110 Interventional Cardiology

**5.4. Atrial septal defect**

**5.5. Emergent surgery**

**6. Special considerations**

**6.1. LAA/LAA thrombus**

Restenosis is not infrequent after percutaneous or surgical commissurotomy. As a growing population, these patients account for one-third of all MS patients in developed countries. Depending on the mechanism, commissural fusion is not predominant in some cases, which limits the role of BMV as an effective intervention. BMV is a feasible option in patients with significant restenosis after percutaneous, closed, or open valvulotomy as long as the commissural fusion is present and valve anatomy is favorable [38]. Immediate and mid-term results are encouraging but might be slightly less satisfactory than with *de novo* MS.

#### **6.3. Pregnancy**

Significant hemodynamic burden caused by pregnancy, labor, and delivery might be not well-tolerated by patients with severe MS. Patients with severe MS often experience worsening of the symptoms or become symptomatic for the first time during pregnancy. Not surprisingly, MS is detected for the first time in many patients during pregnancy. If left untreated, severe MS is associated with a high maternal and perinatal mortality, not least in those who are highly symptomatic or have AF. The intrapartum and postpartum period carries the highest risk in these patients [39]. In patients who remain symptomatic, despite medical therapy, BMV should be performed because the surgery is associated with very high risk of fetal death [40]. BMV is an effective and safe method for relieving MS in pregnant women when performed by highly experienced operators. It has been reported that BMV during pregnancy has a high success rate and excellent short-term results and provides normal eventless deliveries in the majority of patients. In addition, stillbirth is infrequent and most babies have normal growth and developmental patterns [41, 42]. From a practical point of view, to avoid radiation during organogenesis, the procedure should be performed after the 12th week or ideally after the 20th week. The lead shields should cover the abdomen and pelvis and behind the patient. Fluoroscopy time should be minimized as much as possible. The Inoue balloon technique seems to be the preferred method considering shorter fluoroscopy time and inflation-deflation cycle of the balloon. Special care should be taken about the gravid uterus, possible difficulties in the passage of the equipment through the compressed inferior vena cava, and the chance of hypotension and subsequent fetal distress when the mother lies for a long period of time. The balloon size should be selected with great caution. A balloon 1 size smaller than the RS-matched is preferable in borderline cases. The more conservative method of measuring the inter-commissural diameter can be used for balloon sizing in these patients. The stepwise balloon dilatation of 0.5 mm is advisable, and aggressive balloon dilatation is necessarily avoided because it might result in severe MR and subsequently needs urgent surgery, which is unacceptably hazardous to mother and child. TEE can assist in the transseptal puncture, balloon positioning, and stepwise inflations and can limit fluoroscopy time. However, it needs general anesthesia in many cases, requiring that the position of the patient be changed to lateral decubitus to prevent hypotension in prolonged procedures.

#### **6.4. Inoperable patients**

BMV might be an option in patients who are old and have significant comorbidities. Given the suboptimal results and the higher incidence of complications arising from unfavorable morphologic characteristics of the mitral valve and poor condition of patients, BMV should be only used in highly symptomatic patients. In these patients, a more conservative BMV strategy is suggested. The Inoue technique is more appropriate because it is less demanding and provides a faster and smoother procedure. A balloon 1 size smaller than the RS is chosen, followed by a further stepwise dilatation of 0.5 mm. The final result should be judged on an individualized basis. Definitely, a smaller MVA is sufficient in most patients in exchange for severe MR and the difficulty in its management.
