Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website https://www.cardiologyres.org

Original Article

Volume 13, Number 6, December 2022, pages 357-371

High Prevalence of Cardiac Amyloidosis in Clinically Significant Aortic Stenosis: A Meta-Analysis

Figure 6. Funnel plots for analysis of publication bias: (a) Age; (b) Males; (c) RBBB; (d) MCF; (e) LVMI; (f) E/A ratio; (g) Aortic valve (AV) mean pressure gradient; (h) LFLG; (i) All-cause mortality. (a) Age. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.8167, and P = 0.4964, respectively). (b) Males. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.8167, and P = 0.6694, respectively). (c) RBBB. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.3333, and P = 0.6889, respectively). (d) MCF. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.7500, and P = 0.1826, respectively). (e) LVMI. The regression test indicated funnel plot asymmetry (P = 0.0002) but not the rank correlation test (P = 0.0833). (f) E/A ratio. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 1.0000 and P = 0.8009, respectively). (g) AV mean pressure gradient. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.8167 and P = 0.8845, respectively). (h) LFLG. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.7500 and P = 0.1948, respectively). (i) All-cause mortality. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (P = 0.4694 and P = 0.0654, respectively). NT-proBNP: N-terminal pro-brain natriuretic peptide; LVMI: left ventricular mass index; LFLG: low-flow low-gradient; RBBB: right bundle branch block; MCF: myocardial contraction fraction.

**Table 1.** Prevalence of Cardiac Amyloidosis in Patients With Aortic Stenosis Reported in Nine Studies
Studies	AS-CA, %	Total patients
AS-CA: aortic stenosis with cardiac amyloidosis.
Nitsche et al, 2021 [8]	32 (8%)	407
Scully et al, 2020 [9]	26 (13%)	200
Castano et al, 2017 [10]	24 (16%)	151
Singal et al, 2021 [11]	3 (9%)	32
Cavalcante et al, 2017 [12]	9 (8%)	113
Rosenblum et al, 2021 [13]	27 (13%)	204
Treibel et al, 2016 [14]	6 (4%)	146
Oda et al, 2020 [15]	7 (28%)	25
Longhi et al, 2016 [16]	5 (12%)	43
Total	139 (11%)	1,321

Table 1. Prevalence of Cardiac Amyloidosis in Patients With Aortic Stenosis Reported in Nine Studies

Studies

AS-CA, %

Total patients

AS-CA: aortic stenosis with cardiac amyloidosis.

Nitsche et al, 2021 [8]

32 (8%)

407

Scully et al, 2020 [9]

26 (13%)

200

Castano et al, 2017 [10]

24 (16%)

151

Singal et al, 2021 [11]

3 (9%)

Cavalcante et al, 2017 [12]

9 (8%)

113

Rosenblum et al, 2021 [13]

27 (13%)

204

Treibel et al, 2016 [14]

6 (4%)

146

Oda et al, 2020 [15]

7 (28%)

Longhi et al, 2016 [16]

5 (12%)

Total

139 (11%)

1,321

**Table 2.** Characteristics of Studies Included in the Review
Study	Design	Patient population	Primary screening modality for AS-CA	Parameters considered for ATTR-CA	Follow-up	Prevalence of AS-CA	Study center
Tc: technetium; DPD: 3,3-diphosphono-1,2-propanodicarboxylic acid; PYP: pyrophosphate; H/CL: heart-to-contralateral count ratio; MRI: magnetic resonance imaging; ATTR-CA: transthyretin cardiac amyloidosis; TAVI: transcatheter aortic valve implantation; TAVR: transcatheter aortic valve replacement; SAVR: surgical aortic valve replacement; AS: aortic stenosis.
Castano et al, 2017 [10]	Prospective cohort	151 post-TAVR patients	^99mTc PYP	Diffuse ^99mTc PYP uptake, visual score ≥ 2 and H/CL ≥ 1.5. Cardiac biopsy not performed.	Not available	16%	Columbia University’s Center for Interventional Vascular Therapy, USA
Scully et al, 2020 [9]	Prospective cohort	200 patients referred for TAVI	^99mTc-DPD	Perugini grade 1 - 3 indicate increasing uptake. Skewed distribution: none in Perugini grade 3, 69% patients in Perugini grade 2 and 31% patients with Perugini grade 1. Cardiac biopsy was not performed	Median 19 months	13%	Barts Heart Center, London and John Radcliffe Hospital, Oxford, UK
Nitsche et al, 2021 [8]	Prospective cohort	407 patients prior to TAVR	^99mTc-DPD	Perugini grade 2 and 3 regarded as clinical amyloidosis.	Median 1.7 years	8%	3 Centers in Vienna, Austria; Oxford and London, UK
Singal et al, 2021 [11]	Prospective cohort	32 patients prior to SAVR	^99mTc PYP	Diagnosis of ATTR-CA was made based on preoperative ^99mTc PYP scan, intraoperatively obtained interventricular septal biopsy and excised native aortic valve histopathology for ATTR-CA. Perugini grade 2 and 3 and H/CL ratio ≥ 1.5 are considered as significantly positive for diagnosis of myocardial ATTR-CA	1 year	9%	AIIMS, India
Cavalcante et al, 2017 [12]	Retrospective cohort	113 patients with severe AS	Cardiac MRI	Typical late gadolinium enhancement, and morphological findings including increased left ventricular wall thickness and abnormal myocardial and blood pool kinetics were used to identify CA. Four AS patients underwent cardiac biopsy.	Median 18 months	8%	University of Pittsburgh, USA

Table 2. Characteristics of Studies Included in the Review

Study

Design

Patient population

Primary screening modality for AS-CA

Parameters considered for ATTR-CA

Follow-up

Prevalence of AS-CA

Study center

Tc: technetium; DPD: 3,3-diphosphono-1,2-propanodicarboxylic acid; PYP: pyrophosphate; H/CL: heart-to-contralateral count ratio; MRI: magnetic resonance imaging; ATTR-CA: transthyretin cardiac amyloidosis; TAVI: transcatheter aortic valve implantation; TAVR: transcatheter aortic valve replacement; SAVR: surgical aortic valve replacement; AS: aortic stenosis.

Castano et al, 2017 [10]

Prospective cohort

151 post-TAVR patients

^99mTc PYP

Diffuse ^99mTc PYP uptake, visual score ≥ 2 and H/CL ≥ 1.5. Cardiac biopsy not performed.

Not available

16%

Columbia University’s Center for Interventional Vascular Therapy, USA

Scully et al, 2020 [9]

Prospective cohort

200 patients referred for TAVI

^99mTc-DPD

Perugini grade 1 - 3 indicate increasing uptake. Skewed distribution: none in Perugini grade 3, 69% patients in Perugini grade 2 and 31% patients with Perugini grade 1. Cardiac biopsy was not performed

Median 19 months

13%

Barts Heart Center, London and John Radcliffe Hospital, Oxford, UK

Nitsche et al, 2021 [8]

Prospective cohort

407 patients prior to TAVR

^99mTc-DPD

Perugini grade 2 and 3 regarded as clinical amyloidosis.

Median 1.7 years

3 Centers in Vienna, Austria; Oxford and London, UK

Singal et al, 2021 [11]

Prospective cohort

32 patients prior to SAVR

^99mTc PYP

Diagnosis of ATTR-CA was made based on preoperative ^99mTc PYP scan, intraoperatively obtained interventricular septal biopsy and excised native aortic valve histopathology for ATTR-CA. Perugini grade 2 and 3 and H/CL ratio ≥ 1.5 are considered as significantly positive for diagnosis of myocardial ATTR-CA

1 year

AIIMS, India

Cavalcante et al, 2017 [12]

Retrospective cohort

113 patients with severe AS

Cardiac MRI

Typical late gadolinium enhancement, and morphological findings including increased left ventricular wall thickness and abnormal myocardial and blood pool kinetics were used to identify CA. Four AS patients underwent cardiac biopsy.

Median 18 months

University of Pittsburgh, USA

**Table 3.** Quality Assessment of Studies by the Newcastle Ottawa Scale for Cohort Studies
Studies	Selection	Comparability	Outcomes
N/A: not available.
Castano et al, 2017 [10]	★	★	N/A	★★	★	N/A	N/A
Scully et al, 2020 [9]	★	★	N/A	★★	★★	★	★
Nitsche et al, 2021 [8]	★	★	N/A	★★	★★	★	★
Singal et al, 2021 [11]	★	★	N/A	★	★	★	★
Cavalcante et al, 2017 [12]	★	★	N/A	★	★	N/A	★

Table 3. Quality Assessment of Studies by the Newcastle Ottawa Scale for Cohort Studies

Studies

Selection

Comparability

Outcomes

Representativeness of exposed cohort

Selection of nonexposed cohort

Ascertainment of exposure

Assessment of outcome

Duration of follow-up

Completeness of follow-up

N/A: not available.

Castano et al, 2017 [10]

★

N/A

★★

★

N/A

Scully et al, 2020 [9]

★

N/A

★★

★

Nitsche et al, 2021 [8]

★

N/A

★★

★

Singal et al, 2021 [11]

★

N/A

★

Cavalcante et al, 2017 [12]

★

N/A

★

N/A

★

**Table 4.** Patient Demographics
Studies	Cohorts	Age	Males	Hypertension	Diabetes mellitus	Carpal tunnel syndrome	Coronary artery disease	BMI (kg/m²)
N/A: not available; AS-CA: aortic stenosis with cardiac amyloidosis; AS-alone: aortic stenosis; BMI: body mass index.
Castano et al, 2017 [10]	AS-CA	86.3	91.7%	91.7%	N/A	16.7%	75%	25.5
	AS-alone	83.3	63%	84.3%	N/A	5.5%	61.4%	27
Scully et al, 2020 [9]	AS-CA	88	62%	73%	12%	N/A	N/A	N/A
	AS-alone	85	48%	78%	26%	N/A	N/A	N/A
Cavalcante et al, 2017 [12]	AS-CA	88	89%	77.8%	33.3%	N/A	N/A	N/A
	AS-alone	70	56%	73.1%	34.6%	N/A	N/A	N/A
Singal et al, 2021 [11]	AS-CA	72.3	33.3%	33.3%	66.7%	N/A	66.7%	N/A
	AS-alone	69	75.8%	41.4%	20.7%	N/A	31%	N/A
Nitsche et al, 2021 [8]	AS-CA	87.5	65.6%	90.6%	18.8%	18.8%	21.9%	26
	AS-alone	81	48.2%	82.6%	25.6%	1.8%	46.8%	27

Table 4. Patient Demographics

Studies

Cohorts

Age

Males

Hypertension

Diabetes mellitus

Carpal tunnel syndrome

Coronary artery disease

BMI (kg/m²)

N/A: not available; AS-CA: aortic stenosis with cardiac amyloidosis; AS-alone: aortic stenosis; BMI: body mass index.

Castano et al, 2017 [10]

AS-CA

86.3

91.7%

N/A

16.7%

75%

25.5

AS-alone

83.3

63%

84.3%

N/A

5.5%

61.4%

Scully et al, 2020 [9]

AS-CA

62%

73%

12%

N/A

AS-alone

48%

78%

26%

N/A

Cavalcante et al, 2017 [12]

AS-CA

89%

77.8%

33.3%

N/A

AS-alone

56%

73.1%

34.6%

N/A

Singal et al, 2021 [11]

AS-CA

72.3

33.3%

66.7%

N/A

66.7%

N/A

AS-alone

75.8%

41.4%

20.7%

N/A

31%

N/A

Nitsche et al, 2021 [8]

AS-CA

87.5

65.6%

90.6%

18.8%

21.9%

AS-alone

48.2%

82.6%

25.6%

1.8%

46.8%

**Table 5.** Clinical and Echocardiographic Parameters Suggestive of Concomitant Cardiac Amyloidosis (Means Provided in Brackets Where Applicable)
NT-proBNP: N-terminal pro-brain natriuretic peptide; 6MWT: 6-min walk test; ECG: electrocardiogram; RBBB: right bundle branch block; hsTNT: high-sensitivity cardiac troponin; NT-proBNP: N-terminal pro-brain natriuretic peptide; IVS: interventricular septum; LVMI: left ventricular mass index; LFLG: low-flow low-gradient; LA: left atrial; MCF: myocardial contraction fraction; SVI: stroke volume index.
Clinical parameters
Old age (mean 84 vs. 78 years)
Carpal tunnel syndrome
Low 6MWT (127 m vs. 171 m)
ECG
RBBB
Laboratory
Higher hsTNT (53.7 vs. 24.6 ng/L)
Higher NT-proBNP (4,047 vs. 1,803 ng/L)
Echocardiogram (dimensions)
Thick IVS (1.5 vs. 1.3 cm)
Large LVMI (129.8 vs. 103.8 g/m²)
Large LA diameter (4.9 vs. 4.5 cm)
Echocardiogram (Doppler)
Classical LFLG
Higher E/A ratio (1.7 vs. 0.9)
Lower mitral annular S’ (4.5 vs. 6.3 cm/s)
Functional assessment
Low MCF (21.15% vs. 32.5%)
Low SVI (33.1 vs. 39.3 mL/m²)

Table 5. Clinical and Echocardiographic Parameters Suggestive of Concomitant Cardiac Amyloidosis (Means Provided in Brackets Where Applicable)

NT-proBNP: N-terminal pro-brain natriuretic peptide; 6MWT: 6-min walk test; ECG: electrocardiogram; RBBB: right bundle branch block; hsTNT: high-sensitivity cardiac troponin; NT-proBNP: N-terminal pro-brain natriuretic peptide; IVS: interventricular septum; LVMI: left ventricular mass index; LFLG: low-flow low-gradient; LA: left atrial; MCF: myocardial contraction fraction; SVI: stroke volume index.

Clinical parameters

Old age (mean 84 vs. 78 years)

Carpal tunnel syndrome

Low 6MWT (127 m vs. 171 m)

ECG

RBBB

Laboratory

Higher hsTNT (53.7 vs. 24.6 ng/L)

Higher NT-proBNP (4,047 vs. 1,803 ng/L)

Echocardiogram (dimensions)

Thick IVS (1.5 vs. 1.3 cm)

Large LVMI (129.8 vs. 103.8 g/m²)

Large LA diameter (4.9 vs. 4.5 cm)

Echocardiogram (Doppler)

Classical LFLG

Higher E/A ratio (1.7 vs. 0.9)

Lower mitral annular S’ (4.5 vs. 6.3 cm/s)

Functional assessment

Low MCF (21.15% vs. 32.5%)

Low SVI (33.1 vs. 39.3 mL/m²)

**Table 6.** Random-Effects Meta-Regression: Standard Mean Differences and Independent Variables
Effect	AS-CA	AS alone	Estimate	95% CI	Standard error	P value
CI: confidence interval; LL: lower limit; UL: upper limit; AS-CA: aortic stenosis with cardiac amyloidosis; AS-alone: aortic stenosis; hsTNT: high-sensitivity cardiac troponin; NT-proBNP: N-terminal pro-brain natriuretic peptide; 6MWT: 6-min walk test; MCF: myocardial contraction fraction; SVI: stroke volume index.
E/A ratio	1.7	0.9	4.654	3.495	0.592	5.813	< 0.001
hsTNT	53.7	24.6	3.733	2.6	0.578	4.866	< 0.001
NT-proBNP (ng/mL)	4,047.4	1,803.5	3.185	2.331	0.436	4.04	< 0.001
MCF (%)	21.15	32.5	-2.567	-3.566	0.51	-1.567	< 0.001
6MWT (m)	127	171	-2.294	-3.41	0.569	-1.179	< 0.001
SVI (mL/m²)	33.1	39.3	-1.388	-2.324	0.478	-0.452	0.004
Mitral annular S’ (cm/s)	4.5	6.3	-1.031	-2.042	0.516	-0.019	0.046
Intercept			0.224	0.005	0.111	0.442	0.045

Table 6. Random-Effects Meta-Regression: Standard Mean Differences and Independent Variables

Effect

AS-CA

AS alone

Estimate

95% CI

Standard error

P value

CI: confidence interval; LL: lower limit; UL: upper limit; AS-CA: aortic stenosis with cardiac amyloidosis; AS-alone: aortic stenosis; hsTNT: high-sensitivity cardiac troponin; NT-proBNP: N-terminal pro-brain natriuretic peptide; 6MWT: 6-min walk test; MCF: myocardial contraction fraction; SVI: stroke volume index.

E/A ratio

1.7

0.9

4.654

3.495

0.592

5.813

< 0.001

hsTNT

53.7

24.6

3.733

2.6

0.578

4.866

< 0.001

NT-proBNP (ng/mL)

4,047.4

1,803.5

3.185

2.331

0.436

4.04

< 0.001

MCF (%)

21.15

32.5

-2.567

-3.566

0.51

-1.567

< 0.001

6MWT (m)

127

171

-2.294

-3.41

0.569

-1.179

< 0.001

SVI (mL/m²)

33.1

39.3

-1.388

-2.324

0.478

-0.452

0.004

Mitral annular S’ (cm/s)

4.5

6.3

-1.031

-2.042

0.516

-0.019

0.046

Intercept

0.224

0.005

0.111

0.442

0.045