A tale of 3 patients...A short circuit, a steal and the blues

Rami Khouzam, MD

May 20, 2005

Case 1

– A 65 yo AAM with a PMHx. significant for a recent NSTEMI, HTN and ESRD, presented with chest tightness.

– Troponin I: 53 NG/ml (N < 1.5 NG/ml). – Cardiac catheterization: Lt Cx bifurcation lesion

at the level of OM2, and multiple RCA lesions not amenable to intervention.

EKG 1

EKG 2

What Now?

A) Take patient again to the cath. lab

B) Start GIIbIIIa inhibitors

C) Repeat testing of cardiac enzymes

D) Continue same management

E) None of the above

Misinterpretation of ECG due to Cable Malfunction: A Newly Described ECG error.

Fluid contamination at the trunk cable connector impedance change on the V leads’ cable

leading monitor to view V2 through V6 as the same point electrically the cable was subsequently changed

J Electrocardiol, 2005;38:210-211

Case 2Where is the Justice?

Case Report

• O.C. is a 70 y.o. woman who presented with syncope (several episodes in past)

• Denied CP, palpitations, prodrome, incontinence, visual changes, aura, tongue-biting, or post-ictal state

• PMH: HTN, CVA (6 yrs ago), GERD• PSH: CABG 1996, Hysterectomy• SH: occ TOB• FH: CAD, DM • Meds: Accupril, ASA, Prevacid

PE:• T 98.9o P 66 R 16 BP 190/64• HEENT: unremarkable. • Neck: supple without JVD or bruits. • Chest: CTAB. • CVS: RR @ ~60, nl S1/S2, no S3, +S4; PMI NDP II/VI SM @ RUSB -> neck; I/IV DM @ 3rd L ICS.• Abdomen and Neurological exams: unremarkable. • Ext: No edema. • Peripheral pulses 2+ throughout except R radial and

brachial pulses• Orthostats (L arm): supine 210/90, 52; standing

220/100, 56• R arm BP 110/80 mmHg

http://www.geocities.com/davidscerri/unequal_UL_pulses.htm

Differential Dx of Unequal Pulses

• Thoracic Outlet Syndrome• Arteritis (Takayasu’s or temporal)• Embolism• Raynaud’s syndrome• Thoracic Aortic Aneurysm• Thromboangiitis Obliterans• Aortic Dissection• Coarctation of the Aorta• Syphilitic Aortitis• Abnormal Vessel Development• Iatrogenic (e.g., trauma following catheter studies)• Blalock Shunt

• CMP/CBC/CIEs/EKG/CXR/CT head: all WNL• Echo: moderate aortic valve disease (AV area ~1.35 cm2,

gradient ~50 mmHg) AR, AS with intact LV function (EF 65%)

• Carotid duplex USG: R subclavian steal and 60% stenosis of R ICA, 30%

stenosis of R ECA • Arteriogram: tortuous lesion of the proximal R subclavian with an

anomalous retroesophageal course• Axillary-carotid bypass recommended

McIntyre, K., Subclavian Steal Syndrome, eMedicine, Oct 2003.

Subclavian Steal Syndrome

• SSS is caused by occlusion of the proximal subclavian artery with subsequent retrograde filling of the subclavian artery via the vertebral artery

• Definition of SSS must include 1) neuro symptoms due to cerebral ischemia initiated by ipsilateral arm exercise, and 2) diminished BP in the ipsilateral arm due to stenosis or occlusion of the subclavian artery proximal to the vertebral artery origin

• Arch aortogram

• MRA

McIntyre, K., Subclavian Steal Syndrome, eMedicine, Oct 2003

• Atherosclerosis is the most common cause of proximal subclavian artery lesions

• Risk factors include age, sex, FH, smoking, DM, HTN, HPL, hyperhomocystinemia

• Although retrograde blood flow in the vertebral artery is usually noted angiographically with proximal ipsilateral subclavian artery occlusion, subclavian steal may also occur with hemodynamically significant subclavian artery stenosis

El-Mallakh, R.S., Subclavian Steal Syndrome, Ferri's Clinical Advisor, 2004.

• On the right side, only a small distance separates the bifurcation on the subclavian artery and the origin of the vertebral artery; hence, the condition occurs less commonly on the right

McIntyre, K., Subclavian Steal Syndrome, eMedicine, Oct 2003.

Pathophysiology

• Symptoms via flow-related phenomena• Collateral vessels from the subclavian artery

enlarge when the lesion in the proximal subclavian artery progresses

• The upper extremity becomes dependent on collateral vessels distal to the obstruction

• Collaterals serve as points of entry for retrograde flow to the arm from the head, shoulder, and neck

McIntyre, K., Subclavian Steal Syndrome, eMedicine, Oct 2003.

• When arm is exercised, vessels dilate to enhance perfusion to the ischemic muscle and resistance is lowered in the outflow vessels

• Blood is siphoned from the head/neck/shoulders through collaterals to supply this low-resistance vascular bed satisfying increased O2 demand by exercising muscles of the arm

• Resistance in the outflow vessels of the arm increases when exercise ceases

• Retrograde flow in the vertebral artery reduced

Chan-Tack, K., Subclavian Steal Syndrome: A Rare but Important Cause of Syncope, SMA, Apr 2001.

In Essence…

• Development of (-) pressure gradient between vertebrobasilar and vertebral-subclavian artery junctions

• Subsequent retrograde filling of the subclavian artery via the vertebral artery causes the subclavian artery to “steal” blood from the vertebrobasilar system

Clinical: Signs & Symptoms

Muscle crampingCerebral ischemia

- Dizziness- Syncope- Dysarthria

- Visual loss - Diplopia - TIA’s BP differences

El-Mallakh, R.S, Subclavian Steal Syndrome, Ferri's Clinical Advisor: Instant Dx and Treatment, 2004.

• Proximal subclavian occlusion or stenosis CANNOT be present in the absence of a significant difference in BP between patient’s arms

• Therefore, A SIMPLE PHYSICAL EXAM can effectively eliminate significant subclavian arterial lesions without using angiography or duplex ultrasonography

Case 3Out of the Blues

• 18 yr AA woman brought to ER: found comatose at home. Slurred speech, MS changes & inability to move left arm

• 6 wks prior to admission she had delivered a healthy 32 week old infant vaginally

• Delivery complicated by profuse blood loss 2ry. to ruptured vaginal condylomas hematocrit from 49% to 32%

• Exercise intolerance, severe fatigue, SOB: improved after a blood transfusion

Past Medical History• Prolonged hospitalization at birth for almost one

year, but no hx of cardiac surgery

• Some developmental delay followed by a relatively active life & No limitation in daily activities

• Clubbing of fingernails and occasional cyanosis noted by family

Pertinent PE:

• Vitals: P:81, BP:108/54, RR:10

• CVS: Single S2, Normal S1,

RR @ 80 ø m, g, r No JVD

• Lungs: CTA bilat. ø w, c, r

• Ext: clubbing 3rd degree (fingernails &

toenails) +/- cyanosis ø edema

• Neuro: Lt. flaccid hemiparesis:

Lt. Arm > Lt. leg

Current Admission

• In ER: O2 sat. : 65 %

• ABGs: 7.43/ 29/ 41/ 21/ 74%

(post-intubation on 100% O2)

Differential Diagnosis

• Right-to-left shunt:

- Anatomic shunts of systemic venous

blood into the arterial circulation

- Congenital heart diseases

- Pulmonary arteriovenous fistula

- Multiple small intrapulmonary shunts

EKG

Chest X-ray:

• Heart size normal

• No lung infiltrates or interstitial edema

CT of the head without contrast: Normal

TTE (+ contrast echo):

Agitated saline from right femoral vein

TTE (+ contrast echo):

Agitated saline from upper extremity vein

Cardiac cath. Lab:

• PA catheter from right femoral vein

(to left atrium & left ventricle)

• PA catheter from right subclavian vein

(to right atrium, right ventricle & pulmonary artery)

CT-angiogram + coronal reformation, volume rendered color images:

Injection of dye via right femoral vein

MRI/MRA (few days later):

• Hypoplastic vertebro-basilar system

• Area of hypersensitivity in pons suggesting infarct

Le Bonheur Hospital:

Surgery

(Atrial septostomy with repair and transfer of the IVC drainage from left atrium to right atrium)

Outcome

O2 sat. 95 - 100 % on RA

Stable 10 months after D/C

No effort intolerance, No DOE

• In the embryo, the sinus venosus receives the cardinal, umbilical, and vitelline veins.

• It communicates with primitive atrium via an orifice that has a right and left valve.

• Normally, the sinus venosus migrates to the right, and the left valve disappears.

Anomalous Drainage of IVC to the Left Atrium

• The right valve usually decreases in size, becoming the crista terminalis, Eustachian and Thebesian valves.

• If the right sinus venosus valve persists and fuses with the superior part of the septum secundum, the result is:

An Inferior Vena Cava draining into the Left Atrium

Pathophysiology

• If one of the cavae enters the left atrium, the right side of the heart is effectively bypassed so that the right ventricle output and pulmonary blood flow should fall

Meadows, W.R. Am. J. Cardiol. 1965

• The left ventricular output theoretically remains unchanged because the increment in anomalous caval flow into the left atrium is matched by a reciprocal decrement in pulmonary venous flow into the left atrium

• IVC normally carries about twice the volume of blood as the SVC

• Accordingly an anomalously draining IVC delivers a much larger proportion of systemic venous return to the left atrium than an anomalously draining SVC

Perloff. 1994

The History

• Cyanosis from birth or infancy

• Survival into adulthood is the rule with recorded cases in the 6th, 7th & 8th decades

• Absence or paucity of symptoms in patients with cyanosis

Davis, W.H. Br. Heart J. 1959

• Effort intolerance, dyspnea and light-headedness

• Right-to-left shunt (over many decades): paradoxical embolus & brain abcess

• Cause of death: generally unrelated to the congenital malformation

Tuchman, H. Am. J. Med. 1956

Physical Appearance

• Normal except for:

– Cyanosis

– Clubbing

Auscultation• S2: single right ventricular stroke volume and pulmonary capacitance

early pulmonary valve closure synchrony or near synchrony with

aortic closure

Meadows, W. R. Circulation 1961

Diagnosis

The Echocardiogram

• 2-D echo + contrast : Gold standard

Foale, R. Eur. Heart J. 1983

Cyanosis

• Bluish discoloration of lips, nail beds, ears & malar eminences: reduced Hb in small blood vessels

• Central cyanosis: SaO2 < 85 % (Dark-skinned: SaO2 < 75 %) Both mucous membranes & skin• Peripheral cyanosis: Spares mucous

membranes

Clubbing

• In the 5th Century BC, Hippocrates observed that in empyema “the fingernails become curved and the fingers become warm especially at their tips”

• The term “Hippocratic fingers” used in early writings

Campbell, D. BMJ 1924

in thickness of the nail bed and soft tissues of the volar surface followed by connective tissue proliferation, collagen deposition, capillary dilatation, infiltration of lymphocytes and plasma cells

Currie, A.E. Chest 1988

Mechanism of Clubbing

• Right-to-left shunt:

Megakaryocytes (platelet precursors) bypass pulmonary circulation systemic circulation lodge in the tips of the digits (prevailing pattern of blood flow)

Dickinson, CJ. Eur. J. Clin. Invest. 1993

• Once impacted in the capillaries of the digits and periosteum : release:

- VEGF (Vascular Endothelial Growth Factor)

- Platelet-Derived Growth Factor

- Hypoxia-inducible factor-1 - Hypoxia-inducible factor-2

Border, WA. N. Engl. J. Med. 1994

Am J Med Sci 2005;329(3): 1- In press

OUT OF THE BLUES

Out of the Memphis blues

Out of the Heart’s blues Out of the baby blues

“A Tale of 3 Patients…” What have we learned?

• Don’t trust “Medicine by rumor”, always check for yourself

• No technology will replace the importance of a good physical exam

• You can publish publishable cases

• Learning is an ENDLESS process