The Carbomedics Top Hat

Supra-Annular Aortic Valve: A

22-year single-surgeon

experience.

Kinga Kosiorowska

Edward J Caruana

Ian M Mitchell

Trent Cardiac Centre, Nottingham, UK

Background

• The Carbomedics Top Hat (CM-TH) aortic prosthesis

was designed to lie in the supra-annular position, thus

facilitating insertion of a larger valve.

• The low-profile mount offers a larger effective orifice

area (EOA) in sizes 23+ [vs Carbomedics Standard

(CM-St)].

Background

• Higher-positioning of the valve allows for deeper

anchoring sutures to be taken; of particular value in

fragile tissues.

• The large sewing ring adapts to the irregular contours

of calcific aortas; possibly reducing paravalvular leaks.

• Despite concerns of compromising coronary flow and

perfusion, this has never been encountered clinically by

the authors.

Purpose

• To report on a vast single-surgeon experience with

supra-annular mechanical valves (CM-TH), spanning

22-years of consultant practice.

Methods

• All patients receiving the Carbomedics Top Hat (CM-

TH) aortic valve prosthesis between 1995 and 2017

identified from prospective local cardiac surgical

database - single-surgeon, single-centre (UK).

• Contemporary control-group receiving Carbomedics

Standard (CM-St) aortic valve prosthesis identified -

same-surgeon, same-centre.

• Survival data obtained from national database (NHS

Spine).

Methods

• Descriptive statistics, Pearson’s chi squared and two-

way analysis of variance (ANOVA) performed using the

Analyse-it® package for Microsoft Excel 365.

• Kaplein Meier analysis performed using Stata/IC

(v14.1).

• Propensity-matching (1:1) of CM-TH with CM-St

control, modelled on age, gender, NYHA functional

class, BSA, LVEF, and logistic EuroSCORE was

performed in R Statistics (v3.4.3).

Results CM-TH Frequency

N = 244

Results CM-TH Baseline Characteristics

Age (y) 61±10

Male 138 (57%)

BSA (sqm) 1.9±0.3

LVEF

good

moderate

201 (82%)

30 (12%)

PCS 14 (6%)

Log EuroSCORE

(%) 5.3±4.9

Valve Pathology

AS

AS & AR

141 (58%)

57 (23%)

Results CM-TH Operative Data

Procedure

isolated AVR

concomitant CABG

175 (72%)

51 (21%)

Urgency

elective

urgent

203 (83%)

40 (16%)

CPB Time (min) 94±27

X-Clamp Time (min) 70±18

Results CM-TH Valve Data

Valve Size Implanted Patient-Prosthesis Mismatch ‘moderate’ if 0.65-0.85, ‘severe’ if <0.65.

Results CM-TH Post-Operative Survival

Survival

30-day

1-year

5-year

10-year

237/244 (97%)

222/234 (95%)

136/164 (83%)

81/110 (74%)

Results Propensity Matching

Results CM-TH vs CM-St Baseline Characteristics

CM-St CM-TH

(all) p-value

CM-TH

(matched) p-value

N 113 244 - 113 -

Age (y) 61±10 61±10 NS 61±10 NS

Male 90 (80%) 138 (57%) <0.0001 67 (60%) 0.0009

BSA (sqm) 1.9±0.2 1.9±0.3 NS 1.9±0.4 NS

LVEF

good

moderate

64 (57%)

41 (36%)

201 (82%)

30 (12%)

<0.001

73 (65%)

27 (24%)

NS

PCS 6 (5%) 14 (6%) NS 8 (7%) NS

Log EuroSCORE

(%) 6.2±9.2 5.3±4.9 NS 6.1±5.7 NS

Valve Pathology

AS

AS & AR

58 (51%)

20 (18%)

141 (58%)

57 (23%)

0.03

59 (52%)

30 (27%)

NS

Results CM-TH vs CM-St (Matched) Peri-Operative Data

CM-St CM-TH p-value

Procedure

isolated AVR

concomitant CABG

79 (70%)

28 (25%)

84 (74%)

22 (20%)

NS

Urgency

elective

urgent

95 (84%)

16 (14%)

92 (81%)

20 (18%)

NS

CPB Time (min) 98±28 94±28 NS

X-Clamp Time (min) 76±19 70±17 0.01

Valve Size (med,

IQR) 23 (21-25) 23 (21-23) 0.02

PPM

moderate

severe

45 (40%)

10 (9%)

18 (16%)

1 (1%)

<0.0001

Results CM-TH vs CM-St (Matched) Survival Data

Limitations

• retrospective analysis of generic prospectively-

populated database

• no haemodynamic or medium-to-long term complication

data

• no quality of life measures

• low-generalisability (single-surgeon, single-centre)

Conclusions

• There is a lower incidence of PPM in patients receiving

CM-TH vs CM-St (MD -32%).

• The Carbomedics Top Hat aortic prosthesis is safe,

with excellent long-term outcomes, comparable to that

of other mechanical valves.

Thank you. edwardcaruana@nhs.net

attendance and this presentation supported by: