Surgical outcome of partial Shone complex

Abstract

Partial forms of Shone complex are rare. Surgical outcomes of the complete forms have generally been poor, whereas there is a lack of data on long-term follow-up of surgically treated adult partial complex. Between 2001 and 2011, nine patients (age: 38 ± 8 years; six males, 67%) were referred for valvular heart disease. Transthoracic and transoesophageal echocardiography was performed. Data were confirmed by intra-operative findings and reports. Patients were diagnosed as partial Shone complex and presented with mitral stenosis (MS) (45%) or mitral regurgitation (22%) or aortic regurgitation (22%). All but one patient (89%) reported previous surgery: coarctation of the aorta repair (87.5%) and aortic valvulotomy (12.5%). Redo intervention included: mitral valve replacement (25%), mitral repair (25%), aortic valve replacement (37.5%) and subvalvular aortic ridge resection (25%). One patient refused surgery. Patients surgically treated before the age of 5 (87.5%) showed favourable outcome (survival rate: 100%) and a 23.6 (± 4.6)-year follow-up free from events. The patient who underwent first intervention at the age of 50 and the patient with MS who refused surgery showed a 45 (± 7)-year follow-up free from major morbidity. Patients with partial Shone complex, properly diagnosed and treated, show favourable surgical outcome free from major clinical events.

INTRODUCTION

In 1963, Shone et al. originally described the developmental complex that includes parachute deformity of the mitral valve (PMV), supravalvular mitral ring (SVMR), subaortic ridge (membranous or muscular) and coarctation of the aorta (CoA) [1–4].

Complete Shone complex in children is well recognized and there are few case reports of the complex diagnosed in adults. Several series have reported poor outcomes from early aggressive surgical repair [5–9]. However, the partial forms, characterized by two or three of the obstructive components (Fig. 1), have been described rarely in adults [10–15]. Variability in presentation and severity of individual lesions has made appropriate management of the disease challenging. Objective of this work is to report the long-term follow-up of a small population affected by this rare syndrome undergone to early surgery and referred for symptomatic and apparently acquired valvular heart disease.

Figure 1:

Examples of the common inflow and outflow obstructive lesions in Shone complex. (a) supramitral shelf (arrows); (b) aortic coarctation; (c) subaortic ridge (open arrow), bicuspid aortic valve (arrows); (d) parachute mitral valve.

PATIENT POPULATION AND METHODS

Between 2001 and 2011, nine patients (age: 36 ± 10 years; six males, 67%) were referred at San Raffaele Hospital in Milan for progressive worsening of valvular heart disease. All data concerning the past clinical history were reviewed through medical reports, including preoperative invasive and non-invasive evaluations, surgical reports and outpatient follow-up notes. The clinical follow-up and the surgical outcome have been related to the period between the first intervention and the last clinical observation.

Assessment of cardiac morphology

All patients had been evaluated by new echocardiographic study at our institute. Transthoracic and transoesophageal echocardiography was performed for preoperative assessment of valvular heart disease responsible for clinical symptoms as well as for intra-operative monitoring of repair surgery. In the study population, the diagnosis of incomplete Shone complex was based on the presence of two or three of the obstructive lesions in adults (Fig. 1). Echocardioghraphic data obtained were confirmed by intra-operative findings and surgical reports.

RESULTS

Nine patients were diagnosed as having partial Shone complex by our cardiology team. Diagnosis was made, considering the anatomic findings in association to the previous surgical interventions (Table 1).

Table 1:

Echocardiographic patterns of incomplete Shone syndrome in the study population

	LV inflow lesions		LVOT lesions
	SVMR	Mitral valve morphology	Subaortic obstruction	Aortic valve	Previous findings
Patient 1	No	PMV	Yes	Bicuspid	CoA repair
Patient 2	No	PMV	No	Bicuspid	CoA repair
Patient 3	No	PMV	Yes	Bicuspid	CoA repair
Patient 4	No	PMV	No	Bicuspid	CoA repair
Patient 5	No	PMV	No	Tricuspid	CoA repair PDA
Patient 6	No	PMV	No	Bicuspid	Congenital Ao stenosis
Patient 7	No	PMV	No	Bicuspid	Hyopoplastic ascending Ao
Patient 8	Remnants of SVMR	PMV	No	Bicuspid	CoA repair PLSVC
Patient 9	No	PMV	No	Tricuspid	CoA repair

LV: left ventricle; LVOT: left ventricular outflow tract; SVMR: supravalvular mitral ring; PMV: parachute mitral valve; CoA: coarctation of the aorta; PLSVC: persistent left superior vena cava.

Clinical presentation and morphological patterns

All patients presented with symptomatic valvular heart disease (NHYA: 2.5 ± 0.5); severe mitral stenosis (MS) (four patients, 45%) or mitral regurgitation (MR) (two patients, 22%) or severe aortic regurgitation (AR) (three patients, 33%). In all patients, the echocardiographic study revealed morphological patterns of incomplete adult Shone syndrome (Table 1). PMV was the prevalent anatomic finding (100%) (Figs 2a and 3), being associated with critical MS in four patients (45%) and with severe MR from flail anterior and posterior leaflets, respectively, in two patients (22%). The echocardiographic patterns of PMV are summarized in Table 2. Bicuspid aortic valve was the second most common anomaly (seven patients, 78%) and various degrees of AR were noted. Subaortic obstruction was present in two patients (22%); one patient (11%) presented hypoplastic ascending aorta without coarctation and one patient (11%) showed a remnant of SVMR (Fig. 3). No accurate data concerning cardiac size, pressure gradients and coronary anatomy were available.

Figure 2:

(a) Transthoracic short-axis views showing asymmetrical mitral orifice (white arrows) with unique papillary muscle. (b) Suprasternal views showing the residual narrowing of the aortic isthmus (yellow arrow). M: mitral valve; Ao: aorta.

Figure 3:

Transthoracic apical views illustrating a ‘parachute mitral valve’ associated with MS (yellow arrows) and remnants of SVMR (white arrows). LV: left ventricle; LA: left atrium; MS: mitral stenosis; SVMR: supravalvular mitral ring.

Table 2:

Echocardiographic patterns of parachute mitral valve

Echocardiographic view	Morphological pattern
LV long-axis view	Shortened/thickened or elongated chordae converge into a single papillary muscle
LV short-axis view	Basal level: parachute leaflets
	Mid-papillary level: single papillary muscle
4C view	Pear-shaped mitral configuration with diastolic dome shape

LV: left ventricle; 4C: four-chamber.

Surgical interventions

Previous and current surgical procedures of the study population are shown in Table 3. All but one patient had a clinical history of previous surgical intervention; aortic coarctation repair in seven patients (87.5%) (Fig. 2b), and surgical valvulotomy for congenital aortic stenosis in one patient (12.5%). Current redo intervention included mitral valve replacement  (two patients, 25%) and valve repair (two patients, 25%). Three patients (37.5%) had aortic valve replacement (AVR) and two patients (25%) underwent subvalvular aortic ridge resection. One patient with MS refused surgery (11%).

Table 3:

Clinical course of the population study and long-term follow-up

	Age at first intervention	Previous intervention	Reason for referral	Current intervention	Follow-up freedom from clinical events/reintervention
Patient 1	4 months	CoA repair	MR	MVR	228 months/19 years
				Subvalvular aortic ridge resection
				Left atrial ablation
Patient 2	5 years	CoA repair	MR	Mitral valve repair	276 months/23 years
				Ring annuloplasty
Patient 3	50 years	CoA repair	AR	AVR	24 months/2 years
				Subvalvular aortic ridge resection
Patient 4	4 months	CoA repair	AR	AVR	348 months/29 years
Patient 5	6 months	CoA repair	MS	Mitral commissurotomy	300 months/25 years
		Reintervention/PTA		Papillary muscle splitting
				Posterior leaflet extension
				Ring annuloplasty
				Left atrial ablation
Patient 6	5 months	Surgical Ao valvulotomy	MS + AR	MVR	192 months/16 years
		Percutaneous valvuloplasty		AVR
				Left atrial ablation
Patient 7	No	None	MS	None	480 months/40 years
Patient 8	2 years	CoA repair	MS	None	324 months/27 years
Patient 9	1 year	CoA repair	MS	None	314 months/26 years

CoA: coarctation of the aorta; MR: mitral regurgitation; AR: aortic regurgitation; MS: mitral stenosis; MVR: mitral valve replacement; AVR: aortic valve replacement.

Clinical follow-up and surgical outcome

The entire clinical course of the study population is shown in Table 3. Among patients who underwent multiple interventions (Patients 5 and 6), since all treatments occurred in a short-period of time (12 months), the last procedure was considered the starting point of clinical follow-up. Most patients (seven patients, 87.5%) required their first intervention early in life (median age: 16 ± 20 months; range, 4 months to 5 years), whereas one patient (12.5%) had first intervention at the age of 50 years. Patients who had early surgery, before age of 5 years (seven patients, 87.5%), showed a favourable long-term surgical outcome, with the survival rate of 100% and a 23.6 (± 4.6)-year follow-up free from clinical events (Fig. 4). The patient who had undergone first intervention at age 50 (Patient 3) and the patient with severe MS who refused surgery (Patient 7) also showed a 45 (±7)-year clinical follow-up free from major morbidity.

Figure 4:

Surgical outcome and freedom from clinical events in the population study.

DISCUSSION

Partial Shone complex is rarely reported, and there is a general lack of data concerning the clinical follow-up in patients undergone to early surgery. The reports in the literature mainly address small groups of children affected by the complete form of the disease, showing that multiple operations are essential during infancy and childhood to correct left ventricular inflow and outflow obstructive lesions.

Other authors reported that most patients initially present for aortic coarctation repair [14]. Also in our report, most patients were treated during childhood for critical CoA associated with minimal or subclinical signs of left ventricular inflow pathology.

In the complete form, the severity of the obstructions in the left heart dictates the clinical outcome: SVMR and/or additional obstructive lesions usually lead to rapidly progressive pulmonary hypertension and cardiomyopathy. In this setting, ‘critical obstructive lesions’ may obscure other subclinical inflow lesions. In the incomplete forms diagnosed in our experience, after CoA repair had removed early symptoms, patients remained asymptomatic for a long period of time, until a progressive anatomic or valvular lesion triggers new clinical symptoms. Also in the partial form, the first surgical intervention is performed early in life and the following asymptomatic time-frame may be longer and better-tolerated until new worsening of valvular lesions (i.e. flail mitral leftlet, AR or MS), whose progression is favoured by the common congenital background. Because no previous sufficiently detailed echocardiographic data were available, the analysis of the disease progression resulted quite difficult in the population.

As far as our small population is concerned most patients required early surgical intervention and remained asymptomatic for an average time of a 23.6 (± 4.6) years, and were unaware of the rare disease affecting them. Moreover, prior to the appearance of symptoms that required CoA repair, Patient 3 had a 50-year clinical follow-up free from major events, while Patient 7 revealed a 40-year time-frame free from major morbidity before worsening of MS, confirming the variability and severity of the partial Shone complex. The incomplete form of the syndrome may therefore identify a mixed population in which children operated early in life and adults, with less obstructive lesion, can coexist.

Long-term follow-up clearly shows the good results in terms of clinical outcome following surgical treatment of early obstructive lesions. It should be therefore emphasized that appropriate assessments of the disease is undertaken in adult patients presenting with previous CoA repair and apparently acquired valvular heart disease [15]. Awareness of the partial form of the complex is pivotal in appropriate management of the disease.

CONCLUSIONS

Patients affected by partial Shone complex, if properly diagnosed and surgically treated and followed up, show a favourable surgical outcome from first intervention. Notwithstanding the need for reintervention with high rates of valve replacement surgery of one or both left-sided valves, a long-term clinical follow-up free from major events can be achieved.

Conflict of interest: none declared.